Showing posts with label Martinsburg formation. Show all posts
Showing posts with label Martinsburg formation. Show all posts

Sunday, February 24, 2013

Rafinesquina brachiopod from the Martinsburg formation

When visiting rock and fossil shows or shops I always keep and eye out for items from Pennsylvania. Swatara Gap material especially so since that is a now closed site and I only collected there once or twice as a child.

This plate caught my eye because of the large, detailed Rafinesquina brachiopod. It is preserved in a very fine grained sandstone (or sandy mudstone).


Here is another that I collected years ago from the site.

Swatara Gap was a well known collecting site up until about ten years ago when the Pennsylvania Department of Transportation buried the site to prevent undercutting of I-81. The Martinsburg formation is dated to the late Ordovician (Katian stage or Tentonian to Edenian of N. America stages)

Friday, February 22, 2013

Taeniaster spinosus starfish from Pennsylvania

This is a piece of mudstone from the Martinsburg formation at Swatara Gap, PA with parts of a fossil starfish called Taeniaster spinosus.




Swatara Gap was a well known collecting site up until about ten years ago when the Pennsylvania Department of Transportation buried the site to prevent undercutting of I-81. The Martinsburg formation is dated to the late Ordovician (Katian stage or Tentonian to Edenian of N. America stages)