pilot789 0 Posted September 5, 2016 About 3"X2"X1.25" Found in a friend's yard, a friend who collects fossils. He doesn't remember where he got it. But it is most likely from the Miocene Greeensands of the Gay Head Cliffs, and represents some bone of a marine mammal. The end is extremely smooth and shiny, looks a lot like a bone. It is a heavy chunk of rock. A seal bone? Small whale? This 1934 study is the best reference that I've found for the 100-million year old geology of the Gay Head Cliffs where bones of a camel and a horse were found in a glacial era deposit, and many marine fossils have been found in the greensands. https://archive.org/stream/mobot31753003559371/mobot31753003559371_djvu.txt Share this post Link to post Share on other sites
fifbrindacier 3,915 Posted September 6, 2016 It seems geologic to me, but the aspect of that inner shape looks different from the other parts of the piece, so wait for more knowledgeable's opinion. Share this post Link to post Share on other sites
Jdeutsch 30 Posted September 6, 2016 Might be slag https://www.google.com/search?q=black+slag+rock&espv=2&biw=1292&bih=609&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjkm6KP0fnOAhVJ6mMKHdFHBLgQ_AUIBigB Share this post Link to post Share on other sites
