COLLECTING FOSSILS IN MICHIGAN, PENNSYLVANIA, 

 NEW YORK, AND CANADA 



By G. ARTHUR COOPER 



Assistant Curator, Division of Stratigraphic Paleontology, 

 U. S. National Museum 



To collect fossils needed in current investigations in the Division 

 of Stratigraphic Paleontology, the writer made three separate field 

 trips during the summer of 1937 : a month in Michigan, a week in 

 Pennsylvania, and 2 weeks in the Champlain Valley of New York and 

 southern Canada. 



Michigan. — During three previous trips to Alpena and Petoskey 

 the writer studied the strata and collected fossils from Middle 

 Devonian rocks. The month of June was spent in the vicinity of 

 Alpena, Petoskey, and Onaway in an effort to correct suspected 

 errors in stratigraphy and to collect better specimens of certain kinds 

 of fossils. The results of the work were satisfactory in data collected 

 and important additions to the collection. 



Pennsylvania. — The Tully formation is a stratum lying at the base 

 of the Upper Devonian. Although this formation and its contained 

 fossils are well known in New York, it is largely through the efforts 

 of Dr. Bradford Willard, of the Pennsylvania Topographic and Geo- 

 logic Survey, that rocks of Tully age have been identified in Pennsyl- 

 vania. The writer, because of his familiarity with the New York 

 Tully, was invited by Dr. Willard to examine rocks of this formation 

 in Pennsylvania. A pleasant week was spent with Dr. Willard in 

 tracing this formation from a point near Everett in south-central 

 Pennsylvania northeastward to a point not far south of Pottsville 

 in the east-central part of the State. The Tully outcrop extends from 

 this latter point to Milford near the New York-Pennsylvania line. 



Unlike New York, where the Devonian rocks are nearly flat, these 

 strata in Pennsylvania have been thrown into gigantic folds having 

 in general a northeast-southwest trend. The great anticlines and syn- 

 clines are also complicated by cross-folds, causing the northeast- 

 southwest trending structures to pitch under the surface at places. 

 The outcrops of Devonian rocks thus form elongate and canoe-shaped 

 patterns. 



Dr. W 7 illard and the writer started their studies about 40 miles 

 north of the Maryland State line at the settlement of Eichelburger- 

 town. Here the Tully is 3 feet thick and is composed mainly of lime- 

 stone. The limestone thickens along the Alleghany Front to 35 feet 



