During the middle Eocene, 45-50 m.y.a., a number of freshwater lakes appeared in an arc extending from Smithers, through the modern Cariboo, to Kamloops, the Nicola Valley, Princeton, and Republic, WA. The faulting was followed by a period of volcanism that produced a fine-grained ash. The ash washed into the lakes and because of its texture, and possibly because of low water oxygen levels on the bottoms that slowed decay, plant, invertebrate, and fish fossils were preserved in wonderful detail.
Old NID
54269
