Guy DiTorrice commented on my previous post Southern Oregon Universtity Geology 103 Field Trip:
Interesting to note that some of Oregon’s oldest fossils are found at one of the state’s highest elevations — south of Ashland near Siskiyou Summit! And, that most of the fossils found at the I-5 exposures are from an ocean environment. How did that happen???
It may seem a little strange that oceanic fossils are found so far inland from the ocean. In fact, the last thing you expect to find while going for a walk on Mt. Ashland is a bunch of clam shells. However, there is a reasonable explanation…
Continue reading ‘Comment Response: Ocean Fossils at Siskiyou Summit? Say What?’
On Wednesday Dr. Elliot’s geology 103 class went for a field trip. The main focus was on gathering fossil specimens from various locations. The fossils were all found in the Hornbrook formation, contained within Osberger Gulch Sandstone. The rocks were formed during the Cretaceous, which gives them and the fossils an age of approximately 95,000,000 years.
The interpretation is that the sediments were deposited from a beach or shallow marine environment. The abundance of the shells and the broken state of them suggests a high energy environment, so waves must have been present. By far the most common fossils (and original hard parts) were clams and mussels, but gastropods were also present. One lucky student even found a shrimp.
Dr. Elliot and 2 other students climbing a tilted bed of sandstone on the side of Interstate 5, just south of Ashland.
A nice collection taken inches away from a fault that dampened and softened the surrounding sandstone making it easier to collect
Identifying Fossils
One of the many local scorpions we found. We didn’t kill it in hopes that it would die in a depositional environment somewhere and make a nice fossil.
Trying to remove a fossil from the sandstone.
Relic of time.
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