Showing posts with label trilobites. Show all posts
Showing posts with label trilobites. Show all posts

Thursday, January 11, 2024

PALAEONTOLOGY OF CANADA'S KOOTENAY REGION

The East Kootenay region on the south-eastern edge of British Columbia is a land of colossal mountains against a clear blue sky. 

That is not strictly true, of course, as this area does see its fair share of rain and temperature extremes — but visiting in the summer every view is a postcard of mountainous terrain.

Rocks from deep within the Earth's crust underlie the entire East Kootenay region and are commonly exposed in the areas majestic mountain peaks, craggy rocky cliffs, glaciated river canyons, and rock cuts along the highways. Younger Ice Age sediments blanket much of the underlying rock.

I've been heading to the Cranbrook and Fernie area since the early 1990s. My interest is the local geology and fossil history that these rocks have to tell. I'm also drawn to the warm and welcoming locals who share a love for the land and palaeontological treasures that open a window to our ancient past.  

Cranbrook is the largest community in the region and is steeped in mining history and the opening of the west by the railway. It is also a stone's throw away from Fort Steele and the Lower Cambrian exposures of the Eager Formation. These fossil beds rival the slightly younger Burgess Shale fauna and while less varied, produce wonderful examples of olenellid trilobites and weird and wonderful arthropods nearly half a billion years old. 

Labiostria westriopi, McKay Group
The Lower Cambrian Eager Formation outcrops at a few localities close to Fort Steele, many known since the early 1920s, and up near Mount Grainger near the highway. 

Further east, the Upper Cambrian McKay Group near Tanglefoot Mountain is a palaeontological delight with fifteen known outcrops that have produced some of the best-preserved and varied trilobites in the province — many of them new species. 

The McKay Formation also includes Ordovician outcrops sprinkled in for good measure.

Other cities in the area and the routes to and from them produce other fossil fauna from Kimberley to Fernie and the district municipality of Invermere and Sparwood. This is an arid country with native grasslands and forests of semi-open fir and pine. Throughout there are a host of fossiliferous exposures from Lower Cretaceous plants to brachiopods. 

The area around Whiteswan Lake has wonderful large and showy Ordovician graptolites including Cardiograptus morsus and Pseudoclimacograptus angustifolius elongates — some of our oldest relatives. A drive down to Flathead will bring you to ammonite outcrops and you can even find Eocene fresh-water snails in the region. 

The drive from Cranbrook to Fernie is about an hour and change through the Cambrian into the Devonian which flip-flops and folds over revealing Jurassic exposures. 

Fernie Ichthyosaur Excavation, 1916
The Crowsnest Highway into Fernie follows Mutz Creek. From the highway, you can see the Fernie Group and the site along the Elk River where an ichthyosaur was excavated in 1916. 

The Fernie Formation is Jurassic. It is present in the western part of the Western Canada Sedimentary Basin in western Alberta and northeastern British Columbia. 

It takes its name from the town of Fernie, British Columbia, and was first defined by W.W. Leach in 1914. The town of Fernie is rimmed by rugged mountains tipped with Devonian marine outcrops. In essence, all these mountains are upside down with the oldest layers flipped to the top and a good 180 million years older than those they sit upon. 

Before they were mountains, these sedimentary rocks were formed as sediment collected in a shallow sea or inland basin. About 360 million years ago, the rocks that you see in Fernie today were down near the equator. They road tectonic plates, pushing northeast smashing into the coastline of what would become British Columbia. A little push here, shove there — compression and thrust faulting — and the rock was rolled over on its head — repeatedly. But that is how mountains are often formed, though not usually pushed so hard that they flip over. But still, it is a slow, relentless business. 

Cretaceous Plant Material, Fernie, BC
Within Fernie, there are small exposures of Triassic and Jurassic marine outcrops. East of the town there are Cretaceous plant sites, and of course, the Jurassic 1.4-metre Titanites occidentalis ammonite up on Coal Mountain.

The regional district's dominant landform is the Rocky Mountain Trench, which is flanked by the Purcell Mountains and the Rocky Mountains on the east and west, and includes the Columbia Valley region. The southern half of which is in the regional district — its northern half is in the Columbia-Shuswap Regional District. 

The regional district of Elk Valley in the southern Rockies is the entryway to the Crowsnest Pass and an important coal-mining area. 

Other than the Columbia and Kootenay Rivers, whose valleys shape the bottomlands of the Rocky Mountain Trench, the regional districts form the northernmost parts of the basins of the Flathead, Moyie and Yahk Rivers. 

The Moyie and Yahk are tributaries of the Kootenay, entering it in the United States, and the Flathead is a tributary of the Clark Fork into Montana.

Photo One: Tyaughton Mountain, Mckay Group; Photo Two: Labiostria westriopi, Upper Cambrian McKay Group, Site ML (1998); John Fam Collection; Photo Three: Ichthyosaur Excavation, Fernie, British Columbia, 1916; Photo Four: Cretaceous Plant Fossils, east of Fernie towards Coal Mountain. The deeply awesome Guy Santucci as hand-model for scale. 

Thursday, January 19, 2023

CERATIOCARIS, YE KEN

This braw fellow is Ceratiocaris papilio (Salter in Murchison, 1859) a pod Shrimp from the Silurian mudstones of the Kip Burn Formation in the Midland Valley of Scotland. He would have swam in rising seas filled with crinoids, coral reefs, brachiopods, trilobites and new and exotic fish -- some sporting jaws for the first time.

Ceratiocaris is a genus of extinct paleozoic phyllocarid crustacean whose fossils are found in marine strata from the Upper Ordovician through to the Silurian.

They are typified by eight short thoracic segments, seven longer abdominal somites and an elongated pretelson somite. Their carapace is slightly oval shaped; they have many ridges parallel to the ventral margin and possess a horn at the anterior end.

This tidy specimen is from the Silurian mudstones that characterise the Kip Burn Formation with it's dark laminated silty bands. The lower part of the Kip Burn houses the highly fossiliferous ‘Ceratiocaris beds’, that yield the arthropods Ceratiocaris, Dictyocaris, Pterygotus, Slimonia and the fish Birkenia and Thelodus.

The upper part of the formation, the ‘Pterygotus beds’, contain abundant eurypterid fauna together with the brachiopods Lingula and Ceratiocaris. The faunas in the Kip Burn Formation reflect the start of the transition from marine to quasi- or non-marine conditions in the group.

Ceratiocaris are also well known from the Silurian Eramosa Formation of Ontario, Canada (which also has rather nice eurypterids). Photo credit / collection of: York Yuxi Wang and Tianyi Zhang

Joseph H. Collette; David M. Rudkin (2010). "Phyllocarid crustaceans from the Silurian Eramosa Lagerstätte (Ontario, Canada): taxonomy and functional morphology". Journal of Paleontology. 84 (1): 118–127. doi:10.1666/08-174.1.

M. Copeland; T. E. Bolton (1985). Fossils of Ontario part 3: the eurypterids and phyllocarids. Volume 48 of Life Sciences Miscellaneous Publications. Royal Ontario Museum. ISBN 0-88854-314-X.

Sunday, January 15, 2023

FOSSILS AND GEOLOGY OF THE EAST KOOTENAY REGION

Tanglefoot Mountain. Photo: Dan Bowden
The East Kootenay region on the south-eastern edge of British Columbia is a land of colossal mountains against a clear blue sky. 

That is not strictly true, of course, as this area does see its fair share of rain and temperature extremes — but visiting in the summer every view is a postcard of mountainous terrain.

Rocks from deep within the Earth's crust underlie the entire East Kootenay region and are commonly exposed in the area's majestic mountain peaks, craggy rocky cliffs, glaciated river canyons, and rock cuts along the highways. Younger Ice Age sediments blanket much of the underlying rock.

I have been heading to the Cranbrook and Fernie area since the early 1990s. My interest is the local geology and fossil history that these rocks have to tell. I am also drawn to the warm and welcoming locals who share a love for the land and palaeontological treasures that open a window to our ancient past.  

Cranbrook is the largest community in the region and is steeped in mining history and the opening of the west by the railway. It is also a stone's throw away from Fort Steele and the Lower Cambrian exposures of the Eager Formation. These fossil beds rival the slightly younger Burgess Shale fauna and while less varied, produce wonderful examples of olenellid trilobites and weird and wonderful arthropods nearly half a billion years old. 

Labiostria westriopi, McKay Group
The Lower Cambrian Eager Formation outcrops at a few localities close to Fort Steele, many known since the early 1920s, and up near Mount Grainger near the highway. 

Further east, the Upper Cambrian McKay Group near Tanglefoot Mountain is a palaeontological delight with fifteen known outcrops that have produced some of the best-preserved and varied trilobites in the province — many of them new species. 

The McKay Formation also includes Ordovician outcrops sprinkled in for good measure.

Other cities in the area and the routes to and from them produce other fossil fauna from Kimberley to Fernie and the district municipality of Invermere and Sparwood. This is an arid country with native grasslands and forests of semi-open fir and pine. Throughout there are a host of fossiliferous exposures from Lower Cretaceous plants to brachiopods. 

The area around Whiteswan Lake has wonderful large and showy Ordovician graptolites including Cardiograptus morsus and Pseudoclimacograptus angustifolius elongates — some of our oldest relatives. A drive down to Flathead will bring you to ammonite outcrops and you can even find Eocene fresh-water snails in the region. 

The drive from Cranbrook to Fernie is about an hour and change through the Cambrian into the Devonian which flip-flops and folds over revealing Jurassic exposures. On my last visit, I made the trip with local geologist Guy Santucci who swings around the hairpin bends with panache. He is a delight to travel with and interspersed great conversation with tasty bits of information on the local geology.

Fernie Ichthyosaur Excavation, 1916
The Crowsnest Highway into Fernie follows Mutz Creek. From the highway, you can see the Fernie Group and the site along the Elk River where an ichthyosaur was excavated in 1916. 

The Fernie Formation is Jurassic. It is present in the western part of the Western Canada Sedimentary Basin in western Alberta and northeastern British Columbia. 

It takes its name from the town of Fernie, British Columbia, and was first defined by W.W. Leach in 1914. The town of Fernie is rimmed by rugged mountains tipped with Devonian marine outcrops. In essence, all these mountains are upside down with the oldest layers flipped to the top and a good 180 million years older than those they sit upon. 

Before they were mountains, these sedimentary rocks were formed as sediment collected in a shallow sea or inland basin. About 360 million years ago, the rocks that you see in Fernie today were down near the equator. They road tectonic plates, pushing northeast smashing into the coastline of what would become British Columbia. A little push here, shove there — compression and thrust faulting — and the rock was rolled over on its head — repeatedly. But that is how mountains are often formed, though not usually pushed so hard that they flip over. But still, it is a slow, relentless business. 

Cretaceous Plant Material, Fernie, BC
Within Fernie, there are small exposures of Triassic and Jurassic marine outcrops. East of the town there are Cretaceous plant sites, and of course, the Jurassic 1.4-metre Titanites occidentalis ammonite up on Coal Mountain.

Once up at the fossil exposures we begin to look for treasures. Over the next four or five hours, as the heat of the day sets in, we find block after block of dark brown to beige Cretaceous material embedded with coal seams and lithified fossil remains.

The regional district's dominant landform is the Rocky Mountain Trench, which is flanked by the Purcell Mountains and the Rocky Mountains on the east and west, and includes the Columbia Valley region. The southern half of which is in the regional district — its northern half is in the Columbia-Shuswap Regional District. 

The regional district of Elk Valley in the southern Rockies is the entryway to the Crowsnest Pass and an important coal-mining area. 

Other than the Columbia and Kootenay Rivers, whose valleys shape the bottomlands of the Rocky Mountain Trench, the regional districts form the northernmost parts of the basins of the Flathead, Moyie and Yahk Rivers. 

The Moyie and Yahk are tributaries of the Kootenay, entering it in the United States, and the Flathead is a tributary of the Clark Fork into Montana.

Photo One: Tyaughton Mountain, Mckay Group taken by Dan Bowden via drone; Photo Two: Labiostria westriopi, Upper Cambrian McKay Group, Site ML (1998); John Fam Collection; Photo Three: Ichthyosaur Excavation, Fernie, British Columbia, 1916; Photo Four: Cretaceous Plant Fossils, east of Fernie towards Coal Mountain. The deeply awesome Guy Santucci as hand-model for scale. 

Saturday, October 8, 2022

GUT TRILOBITES AND AWESOME POSSUMS

The East Kootenay region of British Columbia boasts glorious mountains, fossils and some of the best folk on Earth. I was doubly blessed to get to spend time immersed amongst all of them this past weekend.

The awesome possum you see in the photo here is Don Askew, an avid fossil hunter from Cranbrook, British Columbia, Canada, who has discovered several new species in the East Kootenays including Aciculolenus askewi, fittingly named after him. 

Don was the first to brave the treacherous cliffs up the waterfall on the west side of the ravine below Tanglefoot mountain. That climb led to his discovery of one of the most prolific outcrops in the McKay Group with some of the most exciting and best-preserved trilobites from the region. 

The faunal set are similar to those found at site one — the first of the trilobite outcrops discovered by Chris New and Chris Jenkins — an hours hike through grizzly bear country.

The specimens found at the top of the waterfall are not in calcite wafers, as they are elsewhere, instead, these exceptionally preserved specimens are found complete with a thin coating of matrix that must be prepped down to the shell beneath. 

Askew was also the skill preparator called upon to tease out the details from the 'gut trilobite' recently published from the region. In all, this area has produced more than 60 new species — many found by Askew — and not all of which have been published yet.

This past weekend, Don, Chris New, Chris Jenkins, Dan Bowen, Betty Franklin caught up and headed out to some fossil exposures near Goat Haven Mountain. Don graciously shared his knowledge and most recent finds for us to examine — a good man that Askew. 

Not surprising then that Brian Chatterton would do him the honour of naming this new species after him. 

Chatterton, Professor Emeritus at the University of Alberta, is an invertebrate palaeontologist with a great sense of humour and a particular love of trilobites. Even so, his published works span a myriad of groups including conodonts, machaeridians, sponges, brachiopods, corals, cephalopods, bivalves, trace fossils — to fishes, birds and dinosaurs.

We found our own treasures over the weekend and came back filled with great memories and wonderful specimens found with friends on a perfect October day. 

Photo One: Don Askew in his happy place finding trilobites near Goat Haven Mountain
Photo Two: Aciculolenus askewi by Chris Jenkins, Cranbrook, British Columbia

Tuesday, August 9, 2022

EAST KOOTENAY PALAEONTOLOGY

Tanglefoot Mountain. Photo: Dan Bowden
The East Kootenay region on the south-eastern edge of British Columbia is a land of colossal mountains against a clear blue sky. 

That is not strictly true, of course, as this area does see its fair share of rain and temperature extremes — but visiting in the summer every view is a postcard of mountainous terrain.

Rocks from deep within the Earth's crust underlie the entire East Kootenay region and are commonly exposed in the area's majestic mountain peaks, craggy rocky cliffs, glaciated river canyons, and rock cuts along the highways. Younger Ice Age sediments blanket much of the underlying rock.

I have been heading to the Cranbrook and Fernie area since the early 1990s. My interest is the local geology and fossil history that these rocks have to tell. I am also drawn to the warm and welcoming locals who share a love for the land and palaeontological treasures that open a window to our ancient past.  

Cranbrook is the largest community in the region and is steeped in mining history and the opening of the west by the railway. It is also a stone's throw away from Fort Steele and the Lower Cambrian exposures of the Eager Formation. These fossil beds rival the slightly younger Burgess Shale fauna and while less varied, produce wonderful examples of olenellid trilobites and weird and wonderful arthropods nearly half a billion years old. 

Labiostria westriopi, McKay Group
The Lower Cambrian Eager Formation outcrops at a few localities close to Fort Steele, many known since the early 1920s, and up near Mount Grainger near the highway. 

Further east, the Upper Cambrian McKay Group near Tanglefoot Mountain is a palaeontological delight with fifteen known outcrops that have produced some of the best-preserved and varied trilobites in the province — many of them new species. 

The McKay Formation also includes Ordovician outcrops sprinkled in for good measure.

Other cities in the area and the routes to and from them produce other fossil fauna from Kimberley to Fernie and the district municipality of Invermere and Sparwood. This is an arid country with native grasslands and forests of semi-open fir and pine. Throughout there are a host of fossiliferous exposures from Lower Cretaceous plants to brachiopods. 

The area around Whiteswan Lake has wonderful large and showy Ordovician graptolites including Cardiograptus morsus and Pseudoclimacograptus angustifolius elongates — some of our oldest relatives. A drive down to Flathead will bring you to ammonite outcrops and you can even find Eocene fresh-water snails in the region. 

The drive from Cranbrook to Fernie is about an hour and change through the Cambrian into the Devonian which flip-flops and folds over revealing Jurassic exposures. On my last visit, I made the trip with local geologist Guy Santucci who swings around the hairpin bends with panache. He is a delight to travel with and interspersed great conversation with tasty bits of information on the local geology.

Fernie Ichthyosaur Excavation, 1916
The Crowsnest Highway into Fernie follows Mutz Creek. From the highway, you can see the Fernie Group and the site along the Elk River where an ichthyosaur was excavated in 1916. 

The Fernie Formation is Jurassic. It is present in the western part of the Western Canada Sedimentary Basin in western Alberta and northeastern British Columbia. 

It takes its name from the town of Fernie, British Columbia, and was first defined by W.W. Leach in 1914. The town of Fernie is rimmed by rugged mountains tipped with Devonian marine outcrops. In essence, all these mountains are upside down with the oldest layers flipped to the top and a good 180 million years older than those they sit upon. 

Before they were mountains, these sedimentary rocks were formed as sediment collected in a shallow sea or inland basin. About 360 million years ago, the rocks that you see in Fernie today were down near the equator. They road tectonic plates, pushing northeast smashing into the coastline of what would become British Columbia. A little push here, shove there — compression and thrust faulting — and the rock was rolled over on its head — repeatedly. But that is how mountains are often formed, though not usually pushed so hard that they flip over. But still, it is a slow, relentless business. 

Cretaceous Plant Material, Fernie, BC
Within Fernie, there are small exposures of Triassic and Jurassic marine outcrops. East of the town there are Cretaceous plant sites, and of course, the Jurassic 1.4-metre Titanites occidentalis ammonite up on Coal Mountain.

Once up at the fossil exposures we begin to look for treasures. Over the next four or five hours, as the heat of the day sets in, we find block after block of dark brown to beige Cretaceous material embedded with coal seams and lithified fossil remains.

The regional district's dominant landform is the Rocky Mountain Trench, which is flanked by the Purcell Mountains and the Rocky Mountains on the east and west, and includes the Columbia Valley region. The southern half of which is in the regional district — its northern half is in the Columbia-Shuswap Regional District. 

The regional district of Elk Valley in the southern Rockies is the entryway to the Crowsnest Pass and an important coal-mining area. 

Other than the Columbia and Kootenay Rivers, whose valleys shape the bottomlands of the Rocky Mountain Trench, the regional districts form the northernmost parts of the basins of the Flathead, Moyie and Yahk Rivers. 

The Moyie and Yahk are tributaries of the Kootenay, entering it in the United States, and the Flathead is a tributary of the Clark Fork into Montana.

Photo One: Tyaughton Mountain, Mckay Group taken by Dan Bowden via drone; Photo Two: Labiostria westriopi, Upper Cambrian McKay Group, Site ML (1998); John Fam Collection; Photo Three: Ichthyosaur Excavation, Fernie, British Columbia, 1916; Photo Four: Cretaceous Plant Fossils, east of Fernie towards Coal Mountain. The deeply awesome Guy Santucci as hand-model for scale. 

Thursday, July 28, 2022

FOSSIL AMMONOIDS OF NEVADA

Time Slows at Berlin-Ichthyosaur State Park
Around half past five, as the first flush of dawn appears, our group was up and ready to visit a site that has been on my bucket list for some time.

High on the hillside up a long entry road sits the entrance to Berlin-Ichthyosaur State Park in central Nevada. It is a short 2-hour drive from our lodgings through orange-hued grasslands and low sloping hills.

A worn American flag and sun-bleached outbuildings greet you on your way to the outcrops. Away from the hustle and bustle that defines the rest of Nevada this place feels remarkably serene. Your eyes squint against the sun as you search for ammonoids and other marine fossil fauna while your nose tends to the assault from the bracing smell of sagebrush.

This site holds many stories. The interpretive centre displays wonderful marine reptiles, ichthyosaurs in situ, as you might expect from the name of the park — but it also showcases years of history lovingly tended. This stretch of dry golden low hills dappled with the yellow of creosote and desert grasses is an important locality for our understanding of the Carnian-Norian boundary (CNB) in North America.

The area is known worldwide as one of the most important ichthyosaur Fossil-Lagerstätte because of the sheer volume of remarkably well-preserved, fully articulated (all the sweet bones laid out all in a row...) specimens of Shonisaurus popularis.

Rich ammonoid faunas outcrop in the barren hills of the Upper Triassic (Early Norian, Kerri zone), Luning Formation, West Union Canyon, Nevada. They were studied by N. J. Silberling (1959) and provide support for the definition of the Schucherti and Macrolobatus zones of the latest Carnian — which are here overlain by well-preserved faunas of the earliest Norian Kerri Zone. 

The genus Gonionotites, very common in the Tethys and British Columbia, is for the moment, unknown in Nevada. The Upper Carnian faunas are dominated by Tropitidae, while Juvavitidae are conspicuously lacking. 

Middle Triassic Ammonoids
Despite its importance, no further investigations had been done at this site for a good 50 years. That changed in 2010 when Jim Haggart, Mike Orchard and Paul Smith — all local Vancouverites — collaborated on a project that took them down to Nevada to look at the conodonts and ammonoids. They did a bed-by-bed sampling of ammonoids and conodonts in West Union Canyon during October of that year.

October is an ideal time to do fieldwork in this area. There are a few good weeks between screaming hot and frigid cold. It is also tarantula breeding season so keep your eyes peeled. Those sweet little burrows you see are not from rodents but rather largish arachnids. 

The eastern side of the canyon provides the best record of the Macrolobatus Zone, which is represented by several beds yielding ammonoids of the Tropites group, together with Anatropites div. sp. 

Conodont faunas from both these and higher beds are dominated by ornate metapolygnthids that would formerly have been collectively referred to Metapolygnathus primitius, a species long known to straddle the CNB. Within this lower part of the section, they resemble forms that have been separated as Metapolygnathus mersinensis. Slightly higher, forms close to Epigondolella' orchardi and a single Orchardella n. sp. occur. This association can be correlated with the latest Carnian in British Columbia.

Higher in the section, the ammonoid fauna shows a sudden change and is dominated by Tropithisbites. Few tens of metres above, but slightly below the first occurrence of Norian ammonoids Guembelites jandianus and Stikinoceras, two new species of conodonts (Gen et sp. nov. A and B) appear that also occur close to the favoured Carnian/Norian boundary at Black Bear Ridge, British Columbia. Stratigraphically higher collections continue to be dominated by forms close to M. mersinensis and E. orchardi after BC's own Mike Orchard.

The best exposure of the Kerri Zone is on the western side of the West Union Canyon. Ammonoids, dominated by Guembelites and Stikinoceras div. sp., have been collected from several fossil-bearing levels. Conodont faunas replicate those of the east section. The collected ammonoids fit perfectly well with the faunas described by Silberling in 1959, but they differ somewhat from coeval faunas of the Tethys and Canada. 

The ammonoid fauna paints a compelling picture of Tethyan influence with a series of smoking guns. We see an abundance of Tropitidae in the Carnian, a lack of Pterosirenites in the Norian, copious Guembelites, the Tethyan species G. philostrati, the stratigraphic position of G. clavatus and the rare occurrence of Gonionotites. Their hallelujah moment was likely finding an undescribed species of the thin-shelled bivalve Halobia similar to Halobia beyrichi — the clincher that perhaps seals this deal on Tethyan influence. 

I'll take a boo to see what Christopher McRoberts published on the find. A jolly good idea to have him on this expedition as it would have been easy to overlook if the focus remained solely on the conodonts and ammonoids. McRoberts has published on the much-studied Pardonet Formation up in the Willison Lake Area of Northeastern, British Columbia. He knows a thing or two about Upper Triassic Bivalvia and the correlation to coeval faunas elsewhere in the North American Cordillera, and to the Boreal, Panthalassan and Tethyan faunal realms. 

If you fancy a read, they published a paper: "Towards the definition of the Carnian/Norian Boundary: New data on Ammonoids and Conodonts from central Nevada," which you can find in the proceedings of the 21st Canadian Paleontology Conference; by Haggart, J W (ed.); Smith, P L (ed.); Canadian Paleontology Conference Proceedings no. 9, 2011 p. 9-10.

Fig. 1. Location map of Berlin-Ichthyosaur State Park

Marco Balini, James Jenks, Riccardo Martin, Christopher McRoberts, along with Mike Orchard and Norman Siberling, did a bed by bed sampling in 2013 and published on The Carnian/Norian boundary succession at Berlin-Ichthyosaur State Park (Upper Triassic, central Nevada, USA) and published in January 2014 in Paläontologische Zeitschrift 89:399–433. That work is available for download from ResearchGate. The original is in German, but there is a translation available.

After years of reading about the correlation between British Columbia and Nevada, I had the very great pleasure of walking through these same sections in October 2019 with members of the Vancouver Paleontological Society and Vancouver Island Palaeontological Society. It was with that same crew that I'd originally explored fossil sites in the Canadian Rockies in the early 2000s. Those early trips led to paper after paper and the exciting revelations that inspired our Nevada adventure.

If you plan your own adventure, you'll want to keep an eye out for some of the other modern fauna — mountain lions, snakes, lizards, scorpions, wolves, coyotes, foxes, ground squirrels, rabbits, falcons, hawks, eagles, bobcats, sheep, deer and pronghorns.

Figure One: Location map of Berlin-Ichthyosaur State Park. A detailed road log with access information for this locality is provided in Lucas et al. (2007).

Friday, July 8, 2022

EAST KOOTENAY FOSSIL EXPEDITION

Pterocephalia norfordi, McKay Group
A lovely Pterocephalia norfordi trilobite from Upper Cambrian, Furongian strata of the McKay Group, East Kootenay Region, southeastern British Columbia, Canada. 

The McKay Group has been explored extensively these past few years by Chris New and Chris Jenkins of Cranbrook, British Columbia. 

Together, these two avid trilobite enthusiasts have opened up considerable knowledge on the exposures, collaborating with researchers Brian Chatterton and Rudy Lerosey-Aubril. They have unearthed many new specimens and several new species. 

Pterocephalia from this region are relatively common. We also find Wujiajiania lyndasmithae along with a host of other Upper Cambrian goodies. 

I collected dozens of well-preserved fully articulated specimens over the course of a week in August 2020, walking in the sacred lands of the Ktunaxa or Kukin ʔamakis First Nations. 

My eyes were good enough to find the specimens themselves, but not as refined as those of Chris Jenkins who spotted the unusual preservation of the embedded gut tract. Brian Chatterton et al. published on it in 1994 and have been following it up year upon year with paper after paper out of these localities. 

Rudy Lerosey-Aubril published a paper in 2017 on phosphatized gut remains — relatively common in this taxon at this site. Lerosey-Aubril’s paper was on an aglaspidid, a combjelly, and the gut of another trilobite. 

Skeletal remains of trilobites are abundant in Palaeozoic rock but soft parts are rarely preserved. 

There have been a few papers on trilobite gut remains from Canada and on abundant trilobite faunas of the Kaili Formation of Guizhou, China. 

The Kaili contains one of the earliest middle Cambrian Burgess Shale-type deposits, sharing many faunal elements with the older Chengjiang Biota (Chen 2004; Hou et al. 2004) and the younger Burgess Shale Biota (Briggs et al. 1994). 

The biota, facies description, and regional stratigraphy of the Kaili Biota were discussed and reviewed in Zhao et al. (2002, 2005) and Lin et al. (2005). 

Their colleagues (Zhao et al. 1994b, 1996, 1999, 2001, 2002) have beautifully illustrated many Kaili arthropods with soft-part preservation, but most of their systematic descriptions are yet complete.

References: Chatterton BD, Johanson Z, Sutherland G. 1994. Journal of Paleontology 68:294-305. 

Lin, Jih-Pai. (2007). Preservation of the gastrointestinal system in Olenoides (Trilobita) from the Kaili Biota (Cambrian) of Guizhou, China. Memoirs of the Association of Australasian Palaeontologists. 33. 179-189. 

Top Photo: This specimen was collected by Dan Bowden and photographed by the Huntress. It has been checked for the dark telltale signs of phosphatized gut remains — sadly no luck!

Middle Photo: Warm summer light atop the mountains and my temporary home-sweet-home. Bottom Photo: Upper Cambrian collecting beds beneath Tanglefoot Mountain, McKay Group, East Kootenay Region, British Columbia, Canada.

Saturday, June 4, 2022

ANCIENT LIFE IN THE EAST KOOTENAYS: ORYGMASPIS SPINULA

Orygmaspis (Parabolinoides) spinula
This calcified beauty is Orygmaspis (Parabolinoides) spinula (Westrop, 1986) an Upper Cambrian trilobite from the McKay Group near Tanglefoot Mountain in the Kootenay Rockies. 

Orygmaspis is a genus of asaphid trilobite with an inverted egg-shaped outline, a wide headshield, small eyes, long genal spines, 12 spined thorax segments and a small, short tail shield, with four pairs of spines.

The outline of the exoskeleton Orygmaspis is inverted egg-shaped, with a parabolic headshield — or cephalon less than twice as wide as long. 

The glabella, the well-defined central raised area excluding the backward occipital ring, is ¾× as wide as long, moderately convex, truncate-tapering, with 3 pairs of shallow to obsolete lateral furrows. 

The occipital ring is well defined. The distance between the glabella and the border (or preglabellar field) is ±¼× as long as the glabella. This fellow had small to medium-sized eyes, 12-20% of the length of the cephalon. These were positioned between the front and the middle of the glabella and about ⅓ as far out as the glabella is wide. 

The remaining parts of the cephalon, the fixed and free cheeks — or fixigenae and librigenae — are relatively flat. The fracture lines or sutures — that separate the librigenae from the fixigenae in moulting — are divergent just in front of the eyes. These become parallel near the border furrow and strongly convergent at the margin. 

From the back of the eyes, the sutures bend out, then in, diverging outward and backward at approximately 45°, cutting the posterior margin well within the inner bend of the spine — or opisthoparian sutures. 

The thorax or articulating middle part of the body has 12 segments. The anteriormost segment gradually narrows into a sideward directed point, while further to the back the spines are directed outward and the spine is of increasing length up until the ninth spine, while the spine on the tenth segment is abruptly smaller, and 11 and 12 even more so. 

This fellow has a wee pygidium or tail shield that is only about ⅓× as wide as the cephalon. It is narrowly transverse about 2× wider than long. Its axis is slightly wider than the pleural fields to each side, and has up to 4 axial rings and a terminal and almost reaches the margin. Up to 4 pleural segments with obsolete interpleural grooves and shallow pleural furrows. The posterior margin has 3 or 4 pairs of spines, getting smaller further to the back. 

References:

Chatterton, Brian D. E.; Gibb, Stacey (2016). Furongian (Upper Cambrian) Trilobites from the McKay Group, Bull River Valley, Near Cranbrook, Southeastern British Columbia, Canada; Issue 35 of Palaeontographica Canadiana; ISBN: 978-1-897095-79-9

Moore, R.C. (1959). Arthropoda I - Arthropoda General Features, Proarthropoda, Euarthropoda General Features, Trilobitomorpha. Treatise on Invertebrate Paleontology. Part O. Boulder, Colorado/Lawrence, Kansas: Geological Society of America/University of Kansas Press. pp. O272–O273. ISBN 0-8137-3015-5.

Monday, June 28, 2021

CAMBRIAN MYSTERIES OF THE CANADIAN ROCKIES

Mount Stephen, Canadian Rockies
High up on the mountain tops of the Canadian Rockies of southeastern British Columbia — on the western edge of Western Canada's Sedimentary Basin — there are mysteries more than half a billion years old. 

Here, for more than a century, palaeontologists have been exploring over a dozen geologic outcrops that speak of a world when arthropods ruled the seas. 

The rocks we walk across are made of shale, thin-bedded limestone, and siltstone deposited during the Middle Cambrian — 513 to 497 million years ago. And these are no ordinary rocks for what they contain — exceptionally preserved soft-bodied fossils of the Burgess Shale biota. 

Charles Doolittle Walcott will be forever remembered for his extraordinary 1909 discovery of the Middle Cambrian Burgess Shale of Yoho National Park in southern British Columbia — delivering to the world one of the most important biota of soft-bodied organisms in the fossil record. Here we find a fairly complete look at an ancient ecosystem with algae, grazers and filter feeders, scavengers and active predators. Remarkably, soft-bodied organisms make up 98% of individuals and 85% of the genera. These animals lived and died in the deep waters at the base of what would later become the Cathedral Escarpment.

In 1908, Walcott wrote, "Nearly every fragment of shale found on the slopes from 2000 to 2600 feet above Field has fossils upon it; not only fragments but usually entire specimens of trilobites.” It was for this reason he returned the following year to collect and the rest, as they say, is history.

The sheer volume and level of preservation were unknown at the time. Walcott's material came from a single section on the west side of the ridge between Mount Wapta and Mount Field and was collected from the main quarry in the Phyllopod bed and the smaller Raymond quarry some 23 m above. 

The Burgess Shale section occurs in the lower two-thirds of the Stephen Formation where the basinal shales abut against the steep face of the adjacent dolomite reef of the Cathedral Formation. The conditions necessary for the preservation of the soft parts of the organisms appear to have been controlled by the proximity of this reef front. Away from the reef front, exceptional preservation is less common.

A view to Mount Stephen, Canadian Rockies
The Burgess Shale was long considered to be a unique occurrence. Then in 1977, Canadian geologist, Ian McIlreath, found that the Cathedral Escarpment or reef front, could be traced for about 20 km southeast of Walcott's quarry and that the contact between the reef and basinal shales cropped out again on Mount Field, Mount Stephen, Mount Odaray, Park Mountain and Curtis Peak. 

Des Collins speculated that more localities of soft-bodied fossils might be found in the basinal shales near these contacts, and, indeed, a few indications were later reported by Aitken and McIlreath (1981) along the line of the Escarpment. 

In 1981 and 1982, we expanded our knowledge of the region. Des Collins and others organized fieldwork that led to the discovery of about a dozen new localities, which Collins et al. published in 1983.

The most promising of the new localities occurred in a large in situ block of pale grey-blue siliceous shale about 1500 m southwest of the outcrop of the Cathedral Escarpment on the north shoulder of Mount Stephen. 

This is about 5 km almost directly south of the Burgess Shale quarries. The site was excavated by a Royal Ontario Museum party in the summer of 1983. Further fieldwork in 1986 led to the discovery of the arthropod Sanctacaris was first described by Briggs and Collins in 1988. 

Sanctacaris uncata, Mount Stephen Fossil Beds

The stratigraphic level where the block occurred is characterized by the trilobite, Glossopleura, which is the local zone fossil for the basal part of the basinal Stephen Formation (Fritz, 1971). 

In the Stephen Formation section of about 1000 m to the north on Mount Stephen measured by Fritz, the top of the Glossopleura Zone is 40 m below the level equivalent to the main Burgess Shale quarry. 

The block excavated was at least 40 m below the top of the Glossopleura Zone. This puts it 80 m or more stratigraphically below the level of the Burgess Shale Phyllopod bed.

The faunal assemblage from the block is dominated by the arthropods, Alalcomenaeua and Branchiocaris, which are very rare in the Burgess Shale. Many other Burgess Shale animals were found (Collins et al. 1983) but surprisingly not the most common — Marrella. They did find many new forms and published their finds in 1986 (Collins, 1986). By all accounts, this fauna is distinct from those in the Burgess Shale — and a shade older. 

But as we learn and gain insight, we also realize how much we have yet to learn. These outcrops help us to gain an understanding of the biology, ecology, diversity and evolution of Cambrian animals in a way that other Cambrian sites cannot. Without this insight, we would have a very limited view of the Cambrian Explosion and see only the shelly fossil assemblages. The unique conditions in the Burgess Shale record species that under typical circumstances, would never have fossilized and would be lost to us forever.

There has been no end of mysteries and riddles to be solved in the designating and correlating units within the Stephen Formation, Burgess Shale Formation, and the Cathedral Formation. Much of the controversy stems from the extensive faulting in the area and especially from environmental (facies) differences between the stratigraphic units. 

There are shelf platform sequences that include shallow water inner detrital belt, middle carbonate belt, and carbonate shelf edge facies, as well as deeper water (basinal) outer detrital belt facies. These have all have posed problems in correlation and descriptions of the formations in the area.

What used to be known as the Stephen Formation is now restricted to what was known as the "thin" Stephen Formation. The Stephen Formation now includes the Narao and Wapituk Members. What was formerly the "thick" Stephen Formation (basinal Stephen) is now called the Burgess Shale Formation. 

Pirania sp., extinct sea sponges, Burgess Shale
This formation comprises units that include the classic Burgess Shale localities (Walcott Quarry (including the "phyllopod bed"), Raymond Quarry), the Mt. Stephen Trilobite Beds, as well as most of the soft-bodied faunas (Collins Quarry, S7, Ehmaniella Zone faunas, etc.).

The Burgess Shale is a UNESCO World Heritage site. The Burgess Shale and Stephen Formations outcrop mainly in Banff and Yoho National Parks in the Alberta-British Columbia border area. All known outcrops are in Canada's Rocky Mountain Parks, so collecting is strictly forbidden. 

While you cannot collect in the parks, you can join in on a guided tour to hike, explore, capturing the beautiful scenery and fossils with your camera and through rubbings. If you fancy a hike to these exalted cliffs, follow the link below.

If an armchair visit is more your thing, pick up a copy of, A Geoscience Guide To The Burgess Shale. This illustrated guide immerses the reader in the history, geology, environment and, most importantly, fossils of the Burgess Shale in an easy-to-read, concise summary of life as it was over 500 million years ago. Excellent colour images of 3D interpretations of the organisms and photos of the fossils make this resource a must-have for anyone interested in the Burgess Shale. 

Burgess Shale Hikes: https://www.burgess-shale.bc.ca/burgess-shale-hikes/  / Toll free: 1 (800) 343-3006; Tel: 1 (250) 343-6006; Email: info@burgess-shale.bc.ca

A Burgess Shale Primer: History, Geology and Research Highlights; Jean-Bernard Caron & Dave Rudkin: https://www.rom.on.ca/sites/default/files/imce/burgess_shale_primer.pdf

References: Palaeontology, Vol 31, Part 3. 1988, pp 779-798, pls 71-73) was discovered by Collins (1986),http://palaeontology.palass-pubs.org/pdf/Vol 31/Pages 779-798.pdf

Image: Reconstruction of Sanctacaris uncata, a Cambrian Habeliidan arthropod (stem-Chelicerata: Habeliida). by Junnn11 @ni075; Pirania sp. & photos: @Fossil Huntress