London, England — My last day in London was spent working on GSA abstracts and examining one last ferruginous oncoid (“snuff-box”) from the Jurassic (Bajocian) of southern England. Bob Chandler donated to the cause a large discoidal snuff-box. We cut it (cross-section through the center shown above) and revealed its intricate internal structure.
The typical limestone nucleus is smaller than I expected, but it still shows typical features such as bioerosion.
This specimen has beautifully-developed “horns” around the periphery. They are made of laminae not connected to the central cortex. Paul Taylor suggested that they form when the snuff-box is no long being moved about. Nice specimen. Cassidy Jester (’17) will have much to figure out in her Independent Study focused on these objects.
I’ve had a great and productive time on this expedition to England. Thank you again to my amigos Tim Palmer and Paul Taylor, as well as John Whicher, Bob Chandler and Consuelo Sendino. Science marches on.
Addendum: This is the way I like my Tube stations — empty! Take me home, District Line to Paddington. Saturday, June 18, 5:08 a.m.
Very cool! They remind me of these:
http://palaios.geoscienceworld.org/content/30/12/836.full.pdf+html
Thanks, Nick! I did not know this article. It will make a fine comparison case.