The lakes likely formed after a period of faulting created depressions in the ground, producing a number of basins or grabens into which water collected - imagine gorgeous smallish lakes similar to Cultus Lake near Chiliwack, British Columbia.
The groaning Earth, pressured by the collision of tectonic plates producted a series of erupting volcanoes around the Pacific Northwest. These spouting volcanoes blew fine-grained ash into the atmosphere and it rained down on the land. 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 beautifully preserved the dead remains of plant, invertebrate, and fish fossils - some in wonderful detail.
In and around the town of Princeton, there are many places to collect. The fossils you find here are all middle Eocene, Allenby Formation and most have a high degree of detail in their preservation.
A crack of the hammer yields fossil maple, alder, fir, pine, dawn redwood and ginko fossil material. Several species of fossilized insects can be found in the area and rare, occasional fossil flowers and small, perfectly preserved fish. It is also home to one of the world's oldest bee's - a find by Rene Saveneye - naturalist and keen paleo hunter who will be much missed.
