A weathered limestone outcrop surface shows an impressive array of the large pygidia (tail shields) of the scutelluine trilobite, Ekwanoscutellum ekwanensis. About 10 fan-shaped pygidia are randomly oriented (upside down and rightside up) in an area measuring about 35 cm x 35 cm. Each pygidium features a short, bluntly tapered axial lobe from around which radiate a series of broad, smoothly rounded ribs.

Another accumulation of Ekwanoscutellum pygidia has been partly excavated from the reef margin. About a dozen complete and fragmentary tail shields are visible on the exposed limestone surface. These are randomly stacked on top of each other in an overlapping array; some are concave up (showing the ventral side) and others show the dorsal surface. A mapping compass sits to the right side and provides scale.

A grey, weathered surface of the exposed reef flank shows faint impressions of multiple Ekwanoscutellum pygidia. Sitting on the surface are two examples of freshly excavated tail shields, with multiple overlapping specimens in each. These are creamy brown in colour and contrast sharply with the old exposure. A marking pen at the right of the image is 14 cm in length and indicates how big the individual pygidia are.

An isolated cluster of Ekwanoscutellum pygidia excavated from one of the reef accumulations and photographed in the lab. The largest, almost fully exposed specimen in the lower centre measures 15 cm in axial length, indicating that the complete trilobite would have been at least 25 cm long.

A #TrilobiteTuesday follow-up to my last 2 #Strataday posts on the #Silurian Attawapiskat Fm, #HudsonBayLowlands. A major goal of #fieldwork was documenting & interpreting multiple accumulations of Ekwanoscutellum ekwanensis #pygidia: dozens of large tail shields nested together in #reef hollows!

Aerial view from helicopter showing a large river channel (flowing left to right) excised in tundra lowlands. Spruce trees line the banks, with patches of muskeg in the background. A large island, and several smaller islets composed of pale grey rock, extend across the dark water of the channel in the middle of the image. Another patch of pale rock is exposed on the far shore behind the main island. Each of the roughly dome-shaped islets and the isolated shoreline outcrop is a single Silurian fossil reef, exhumed in full relief.

A person stands on an exposed rocky outcrop on the shore of a large river. The grey rocks rise about 4 metres above water level and curve gently inland forming a half-dome shape. The rough rocky surface shows the effects of erosion by ice and water. In the background, clear blue sky frames the standing figure.

A closer view of the buff-grey reef-associated limestone with an abundance of fossils exposed within a small open catchment area. Visible at the centre and right-centre are two phragmoceratid cephalopod shells; other fragmentary orthoconic cephalopods are scattered throughout the same pocket. A mapping compass sits on the surface for scale and orientation.

Another close-up of a fractured area of reef surface showing an assortment of fragmentary favositid tabulate corals and cephalopod shells. A small scale gives an indication of size.

Another #Strataday look-back: slide scans from 1995 fieldwork on the early #Silurian (~435 MYA) Attawapiskat Fm. 3-D exhumed #reefs exposed along the Attawapiskat R, #HudsonBayLowlands, #Ontario w amazing #fossil preservation, esp. within reef crevices & cavities, incl. corals & cephalopod molluscs

A person carrying a large backpack is wading away from the camera through shallow water along the rocky shore of a large river. To their left is a vertical cliff face (about 10 metres high) of well-bedded, tan-coloured limestone, topped by brush and spruce trees. On their right is the main river channel, with water breaking over submerged rocky ledges that form a series of rapids reaching to the far densely wooded shore.

An inflatable river boat with outboard motor is hauled up and tied on the rocky shore of the river. A vertical cliff of bedded limestone rises to the left of the boat, partly shadowed by overhanging brush. Behind the boat, rough water of the river rapids can be seen extending across to the far shore. Sun reflects off the river under a partly clouded sky.

Digging into the old 35 mm slide archives for #Strataday: summer 1993 & paleontological fieldwork at remote Grand Rapids on the Mattagami River. Checking mid #Devonian (~394 MYA) marine carbonates of the Kwataboahegan Fm -best vertical exposure in the #HudsonBayLowlands of #Ontario 🇨🇦 #Canada 🇨🇦

This week on #Strataday we're at remote Surprise Ck in the #HudsonBayLowlands, n. #Manitoba & the type section of the Surprise Creek Fm, overlain (just under the lip of the waterfall) by the Caution Creek Fm; Bad Cache Rapids Gp, Late #Ordovician (~450 MYA) - not an easy area to get to or work in! 🇨🇦