Field Notebook: Minnesota, Wisconsin, Iowa, Illinois, Pennsylvania
Page 25
Image from the Biodiversity Heritage Library. Contributed by Yale Peabody Museum of Natural History. | www.biodiversitylibrary.org
Transcription
several specimens of Rhynchonella caja. The Hudson River shales in this region is about 75 feet thick above the lake level. Above this comes the Quijara Limestone forming the cliff the lower layers of which are very chert. Not here are there any good specimens the whole being covered by the Quajara talus.