346 The Upper Devonian Deposits of Maryland 



mainly in the medial beds where Chemung and Portage forms occur com- 

 prising Spirifera disjuncta, Spirifera mesocostalis, Streptorhynchus che- 

 mungensis, Chonetes scitula, and others," ' while Hampshire called from 

 the county of that name in northeastern West Virginia corresponds in a 

 general way to the upper portion of the Catskill formation of southeastern 

 New York. Finally, Clarke and Schuchert propose that the Upper De- 

 vonian be divided into the Senecan and Chautauquan periods or groups; 

 the Senecan composed of the Tully limestone, Genesee shale, and Portage 

 beds which include the terms Naples beds, Ithaca beds and Oneonta beds 

 as local facies of that stage, and the Chautauquan composed of the Che- 

 mung beds of which the Catskill sandstone is given as a local facies/ 



The Maryland Geological Survey adopted Jennings formation for the 

 name of the division succeeding the Eomney for a reason similar to that 

 given in explanation of the Eomney formation. The name Chemung 

 was first used as the name of a stage, but Dana considered it as the 

 name of a period composed of the Portage and Chemung epochs, so that 

 it is in common use as the name of a stage or age, using the terms 

 proposed by the International Congress of Geologists, as well as for 

 the name of the higher division of series or epoch. Jennings was already 

 in use by the Maryland Geological Survey before the publication of the 

 names Senecan and Chautauquan by Clarke and Schuchert and, for 

 convenience in mapping, it was also found better to regard it as one 

 formation. 



The name Hampshire was used in the earlier publications of the Mary- 

 land Geological Survey, instead of Catskill, because of the controversy 

 over the limits of tliat formation in New York, and because the ques- 

 tion had been raised whether, on account of the absence of fossils, it 

 is possible to correlate the upper Devonian red rocks of Maryland and 

 West Virginia with those of New York. Eecognizing the fact, however, 

 that the Catskill formation in different parts of New York represents 

 a different length of geological time, it is believed that the southern 

 red deposits have the same general stratigraphic position and may be 

 followed across Pennsylvania to Maryland. 



'Am. Geol., Vol. x, 1892, p. 18. 



» Science, N. S., Vol. x, 1899, p. 876. 



