The McAbee Fossil Beds (Tranquil Shale, Cache Creek) are some
50 million years old (Eocene). These shales are sediments of
a shallow lake that existed at a time when the Northern hemisphere
had a warm temperate climate. The fossil
record shows that this was a time when palm trees grew as
far north as Alaska. Some five dozen plant species have been
described from the Tranquil shale, including more than 40 Broadleaves
and some 17 Conifer species. Sassafras, katsura and both Ginkgo
plant fossils have been found, as well as a diversity of insects,
fish fossils, and even some feathers.
fossil site is east of the town of Cache Creek, British Columbia
along Highway 97. The fossils record flora and fauna from a
50 million year old forest that grew near and in the mountains
surrounding a lake. The leaves, flowers, seeds and insects of
the forest were transported by wind, rivers and streams into
the lake, where they sank to the bottom, were covered by fine
sediments and diatoms. The fine sediments enabled fossilization
by carbonization, preserving many fine details, making possible
detailed comparisons of the fossils to modern counterparts.
of the McAbee fossils are the first occurrence known of extant
plant species, providing valuable data for the study of plant
evolution and Eocene paleoenvironments. Spruce, fir and pine
trees grew at the higher elevations, with needles, seeds and
cones transported to the lake below. Elm, birch, alder and beech
trees dominated the flora lower down and closer to the lake,
leaving exquisite fossil leaves and plant reproductive parts.
Some two thirds of the fossils are from plant families still
extant, but a large number of rarer leaves have yet to be indentified.
Known and unknown plant species number more than 100, supporting
the theory that the Eocene forests of British Columbia were
more diverse that the modern forests that grow in modern times.