32 The Middle Devonian Deposits of Maryland 



Finally Ivayser has given the correlation of the Middle Devonian of 

 Europe and North America in the following table: 



Ehehdancl 





Belgium 



Bohemia 



North America 



Stringoceplial 



us 



Wissenbach 



H 



Hamilton beds 



liQiestoue, 





and 



G' G'^ G' 

 and 



Marcellus beds 

 Onondaga limestone 



Calceola 





Lenne slates 



Mnenian 



and 



shales 







limestone 



Schoharie sandstone 



Dr. Hermann Credner gives the ^Middle Devonian of Xew York as 

 composed in ascending order of the Upper Helderberg (Onondaga), 

 Marcellus shale and Hamilton sandstone, shale and limestone. The 

 Upper Helderberg he correlates mth the Eifelian and stage of the 

 Calceola sandalina and the Marcellus and Hamilton vith the Givetian 

 and stage of the Stringocephaliis burtitii." 



Sir Archibald Geikie considers the Middle Devonian of Xew York as 

 composed of the Marcellus and Hamilton groups ; ' while the same divi- 

 sion in Europe he gives as composed of the Eifelian and Givetian with 

 which he correlates the ]\Iarcellus and Hamilton.* 



Development of the Classification in Xevp York 



The Geological Survey of 'New York was organized in 1836 and the 

 annual reports contained the preliminary names of the formations which 

 now compose the Devonian and other systems of rocks represented in 

 that state." 



The correlation for the different districts, however, had been more 

 fully perfected when the final reports were published and in these we 

 find, substantially, the list of names which have become classic in the 

 Paleozoic geology of North America. Dr. Emmons' report on the Sec- 

 ond District, which covered northeastern New York, was published in 



^Ibid., p. 179. 



" Elemente d. Geologie, 9th ed., 1902, p. 447. 



' Text-Book of Geology, 4th ed.. Vol. II, 1903, p. 997. '" 



* Ibid., " The Geological Record," opposite p. 861. 



"See especially the 3d and 4th An. Repts., Fourth Geol. Dist. (Assembly 

 Doc. No. 275, 1839, and ibid.. No. 50, 1840), and 4th An. Rept., Third Geol. 

 Dist. (Assembly Doc. No. 50, 1840). 



