. Bulletin of the Geological Society of America. Geology; Geology -- United States. 302 HALL AND SARDESON—PALEOZOIC FORMATIONS OF MINNESOTA. The fossils are: Analoteichia impolita, Ulrich. Pachydictya foliata, Ulrich. Stictoporella frondifera, Ulrich. Leptsena sericea, Sowerby. Lingula elderi, Whitfield. Orthis perveta, Conrad. 0. tricenaria, Conrad. Rhynchonella ainsliei, X. H. Win- chell. R. minnesotensis, Sardeson. Streptorhynchus filitextum, Hall. Zygospira recurvirostris, Hall. Helicotoma planulata, Salter. Murchisonia gracilis, Hall. Pleurotomaria subconica, Hall. Raphistoma lenticulare,
. Bulletin of the Geological Society of America. Geology; Geology -- United States. 302 HALL AND SARDESON—PALEOZOIC FORMATIONS OF MINNESOTA. The fossils are: Analoteichia impolita, Ulrich. Pachydictya foliata, Ulrich. Stictoporella frondifera, Ulrich. Leptsena sericea, Sowerby. Lingula elderi, Whitfield. Orthis perveta, Conrad. 0. tricenaria, Conrad. Rhynchonella ainsliei, X. H. Win- chell. R. minnesotensis, Sardeson. Streptorhynchus filitextum, Hall. Zygospira recurvirostris, Hall. Helicotoma planulata, Salter. Murchisonia gracilis, Hall. Pleurotomaria subconica, Hall. Raphistoma lenticulare, Emmons. Productella Minneapolis, Sardeson. The Stictopora (or upper Blue) Bed.—This layer has a thickness of about 30 feet. It is made up of a dark-green rock, massive rather than shaly in its structure, and quite argillaceous in its composition. It car-. Piguee 7.—Lenticular Segregations of Fossils in the Stictopora Bed, Saint Paul. Lenses consist of closely packed and thoroughly cemented fossils within the muss of calcareous shale. ries a few crystalline slabs composed of firmly cemented fossils (figure 7). This bed weathers so rapidly as to give it the appearance of being very fossiliferous, but it is probably less so than the beds above. It affords a good illustration of effectual weathering when exerted on rock made up of such diverse elements. The fossils are: Raufi lla filosa, Ulrich. R. palmipes, Ulrich. Pachydictya jimbriata, Ulrich. Phylloporina reticulata, Hall. Prasopora contigua, Ulrich. Stictopora mutabilis) Ulrich. Stictoporella cribrosa, Ulrich. ('nutin halli, Sardeson. C. setigera, Hall. C. trentonensis, Hall. Zygospira recurvirostris, Hall. Bellerophon hiloLittnx, Sowerby. Bucania bidorsata, Hall. Cortchopeltis bbtusa, Sardeson. Cyclonema semicarinatum, Salter. Holopea symmetrica, Hall. Murchisonia gracilis, Hall. M. milleri, Hall. M. tricarinata, Hall. Pleurotomaria clivosa, Please note that these images are extracted from scanned page image
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