Source area for Leschi erratic?

Reader Wes Gannaway, a paleontologist in Bellingham, suggests the source area for the bivalve-bearing Leschi erratic could be the rocks around Harrison Lake, BC. He has only seen the photos posted here of the fossils in the erratic, so this is remains a hypothesis only, but I think it is a reasonable one. I have started a separate page in the field trips portion of this website just for this erratic, and will add new info to it as we all learn more. That page is here.

Wes wrote:
“The gray siltstones are along the shore of Harrison Lake and contain
an assemblage of ammonites and clams including the Buchia crassicola, which
I believe are the dominant Buchia species at Fossil Creek in the Nooksack
Group. The formation borders on the Cretaceous/Jurassic boundary, age
equivalent to the Nooksack Group. The fossils are abundant in the Mysterious
Creek Formation. C.H. Crickmay wrote a paper in 1930 on the locality. His
paper names them Aucella sp. and Jeletzky named them Buchia, although
I don’t know enough about the species to identify which one is in the
boulder. Aucella is also found in the Jackass Mountain area. Someone with
the knowledge of the species should take a look at the fossils in the
boulder. I am just looking at the photo and using the general shape and rock
color to call it Buchia from Harrison Lake.”

Thanks for that, Wes. Here’s some more information: (ain’t the web wonderful?)
Here’s another blogger’s post about fossil hunting in the Mysterious Creek Formation. And this blog has photos of large Buchia fossils, including this one.


Further web investigation turns up this abstract of a 1983 UBC MSc done by Andrew Arthur on stratigraphy and fossils in the area. If you follow the above link to the thesis abstract, you’ll find a download file of the entire thesis as a pdf. In it are many photos and drawings of fossils, mostly ammonites, found in the Mysterious Creek and related formations.

As a source region for the Leschi erratic, the Harrison Lake area makes good sense. The Vashon ice flowed south right through there. Any paleontologists out there who want to take a crack at this problem?

Advertisements

One Response

  1. Buchia are abundant in the Spieden Formation on Spieden Island in the northern San Juans. I found a football sized piece of sandstone with ‘Buchia in Olympia while planting rhodies. The late VS Mallory identified them for me.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: