Reports Dealing with the Systematic Geology and Paleontology of Maryland., Volume 6

abundant Altitude appearance argillaceous Bactrites bands base beak becoming beds brown Bull cardinal Catskill Chemung Chonetes Clarke closely Collection.—Maryland Geological Survey common Concealed concentric conglomerate Conrad containing convex County Cumberland curving depressed Devonian differs east exposures extending extremity fauna feet figs fold FORMATION fossils Genesee Genus Geol Grabau green shale Hall Hamilton HAMILTON MEMBER height Hill hinge-line Horizontal impressions Ithaca Jennings lateral length less locality lower Marcellus margin Maryland MEMBER middle miles Mountain Museum National Road nearly occur Onondaga Parkhead Plate plications posterior ridge Road rocks Romney rounded sandstone shell shown shows side similar sinus slightly slope species specimens Spirifer striae surface thickness thin top of beds Town Creek umbonal upper usually valve ventral valve Virginia volution western width Williams Road York zone