Search the Community

Hi! I'm a new user who's really into marine reptile bones, by which I mean mosasaurs and plesiosaurs from the Late Cretaceous strata found where I live. I've recently found a small yet satisfying piece that seems to be a hollow bone of a pterosaur/bird. The age of the strata is Late Campanian/Early Mastrichtian and the rock itself is an erratic piece of an "opoka" - a siliceous limestone typically found in Poland and Germany. The bedrock from which it originates lies very likely underneath the Quarternary cover in what is now the Gdańsk Bay (SE Baltic Sea region). It's hollow inside and when viewed with a 60x magnification LAGs and Haversian Canals are visible. Is it likely to be a bone of some tetrapod, say pterosaur/bird? Or might it come from a fish? (that is, if fish actually posses hollow bones, which I might be not aware of yet). Any answers will be very much appreciated. Excuse me for any writing mistakes, which I might make, I'm not any native English speaker. If any more photos are needed I'll send them right away. Cheers, Simon

Glacial rocks reveal the geology hidden beneath the East Antarctica Ice Sheet Syracuse University, PhysOrg, March 6, 2023 The open access paper is: Fitzgerald, P.G., Goodge, J.W. Exhumation and tectonic history of inaccessible subglacial interior East Antarctica from thermochronology on glacial erratics. Nat Commun 13, 6217 Yours, Paul H.

The Delaware Bay and Delaware River shores are littered with lovely marine erratics. They aren't local. They aren't young. You have to dig pretty darn deep in Delaware just to get to the Cretaceous in some places. These are Paleozoic. Many pieces are limestone and probably from the Mahantango FM. But, I find just as many that are definitely not limestone. They are silicified to cert and other shades of SiO2 plus a bit of dark blue/black mineral. I'm thjingking they are ordovician, based on the Foerstiphyllum sp. corals here. The puzzle is, where do they and the other silicified corals, sponges, bryozoa etc, come from? The DE geological Survey doesn't even mention the erratics. I was told that it's been washed down from the Appalachians. Okay, there are definitely ordovician layers there that could have eroded into the river, but all I can find are formations of limestone and fine-to-very-fine grained sandstone. Been doing all kinds of searching through descriptions of geological formations in the area and I'm coming up blank. Anyone have any ideas?