30 The Middle Devonian Deposits of Maryland 



Mareellus shale aud Hamilton group as forming the upper part of the 

 Middle Devonian and correlated them as beginning in the time of the 

 upper part of the Calceola sandalina stage and continuing through that 

 of the Stringocephalus hurtini of Eheinland/ In this same table the 

 Mareellus and Hamilton considered together are correlated with the 

 upper part of the Eifelian (Calceola shales of Couvin) together with the 

 entire Givetian (which is composed in ascending order of the red sand- 

 stone and conglomerate of Vicht and Stringocephalus limestone of 

 Givet) of Belgium. While they are given as equivalent in England to the 

 llfracombe beds, ■nath probably additional ones below and above, of 

 North Devon; and to the upper part of the Calceola shales of Hope's Nose 

 and Ogwell House succeeded by the diabase and scale stone of the Ash- 

 prington series and the Stringocephalus limestone of South Devon. 



In another part of the work Dr. Freeh in comparing the North Amer- 

 ican and Rhenish Devonian said : In the Corniferous [Onondaga] lime- 

 stone the faunal diversity is less sharply defined than in the lower 

 formations ; but in this case as in the higher Hamilton group still dis- 

 tinctly perceptible. The latter is often developed in the form of sandy 

 marl and calcareous sand and the peculiar faunal similarity with the 

 Ehenish Lower Devonian partly rests upon this hannony in facies. But 

 on the other hand, the marl (j\Ioscow shale), for example, where it forms 

 on Cayuga Lake the greater part of the Hamilton, has a perfect agree- 

 ment in facies with the Calceola marl and likewise the Encrinal lime- 

 stone reminds one of a similar interstratified limestone The fauna 



of the American Middle Devonian, whose chief representatives the Hamil- 

 ton group contains, is notwithstanding some corresponding features yet 

 on the whole so different, that one must assume the existence of a special 

 sea province also in Middle Devonian time differing from the Rhenish.* 

 .... Finally at the close of this section is the statement that the Mar- 

 eellus shale corresponds to the lower part of the stage of the Maeneceras 

 terehratum* of Rheinland which Dr. Freeh puts in the stage of the 

 Siringoceplwhis huriini. 



Ubid., 2 Bd., 1 Lief., 1897, Tab. XIX, op. p. 256. 

 'Ibid., pp. 214, 215. 

 'Ibid., p. 216. 



