Dr. Graham Young, Curator of Geology and Paleontology and Parklands/Mixed-Woods Gallery Project Manager

Climbing along the base of the cliff, our research team came to a place where large rock slabs were covered by strange red-brown structures similar to the seaweeds you find on a seashore. But these were fossils some 450 million years old; beautifully fresh-looking and clearly defined. The soft tissues of plants and animals usually rot away after death. How could these have been preserved?

This area on the west side of Lake Winnipeg has rocks containing fossils unlike any others found in Manitoba. Some may be unique worldwide. It is one of those rare ‘windows’ into the distant past, through which we can see some of the plants or animals that lacked hard body parts. The fossils date from the Late Ordovician Period when a warm sea covered the middle of North America, including Manitoba. I visited this site in June 1997, with a group of scientists from The Manitoba Museum, Manitoba Geological Services, Royal Ontario Museum and the University of Western Ontario. It is far from any road, so we travelled by floatplane.

Camping at the site, we did initial reconnaissance. With the help of volunteer Ed Dobrzanski, I was able to collect specimens of rare and beautiful fossils for the Museum.

We were limited by the weight our aircraft could carry, but were able to bring back examples of all fossil types found. These included a variety of beautiful seaweeds, soft algae similar to those living in oceans today. They were associated with fossils rare in central North America: mesh-like graptolites (distant relatives of vertebrates) and others difficult to classify. There were also more typical Ordovician fossils: crinoids (sea lilies), trilobites (extinct animals similar to horseshoe crabs), cephalopods (relative of squids), conularids (extinct possible jellyfish relatives), sponges and brachiopods (lamp shells).

Bottom sediments may have contained too little oxygen for soft parts to be broken down by bacteria, thus allowing the unusual preservation of this rare assemblage. These sediments were probably deposited in deeper water than other Ordovician ones, such as the famous Tyndall Stone. Conditions on the seafloor were not very suitable for growth of bottom-dwelling plants and animals, and many of the fossils are of swimming and floating organisms. Where bottom-dwellers do occur, they are usually concentrated in specific layers, suggesting temporarily improved bottom conditions. A deep-water environment is also suggested by the absence of rock layers made of seafloor sediments disturbed by storms, because the trilobites and crinoids have not been broken up by waves and currents, and by the lack of shallow-water fossils such as corals.

While the Lake Winnipeg site does not have the diversity of unusual material found at some other localities, it has considerable scientific significance because it dates from shortly before the Late Ordovician mass extinction event, one of the greatest extinctions in the history of life. The fossils collected on this expedition are currently being prepared and catalogued at the Museum; some have already been exhibited. We hope to revisit the site in the next few years to collect more fossils and detailed scientific data, and eventually produce a Museum publication that thoroughly documents this wonderful assemblage.