8 TWENTY-TIIUiD ReFORT OX THE StaTR CABINET. 



arenaceous beds of the Hamilton as the Chemung, by the 

 geologists of these adjacent districts, that such a disposition of 

 the strata could be harmonized. At a later period, investigations 

 in strata, which are clearly above some of the red rocks, revealed 

 the occurrence of characteristic fossils of the Chemung group ; 

 and, relying upon this evidence, we were compelled to the conclu- 

 sion that the Catskill group, as recognized and described in the 

 Reports of the eastern districts, was made up, in j^art at least, of 

 rocks of the age of the Chemung group. Later examinations have 

 confirmed this view, and it now a^^pears that the term "Catskill 

 group" cannot, with propriety, be applied to any other rocks 

 than those of the higher part of the Catskill Mountains and hills 

 adjacent upon the west. Even limiting the term in this manner, 

 the evidence of its identity with the red sandstone of the Tioga 

 valley, in Pennsjdvania, rests upon the fact of its succession to 

 the Chemung group, if that be regarded as demonstrated. It is 

 true that, in the red sandstones of Delaware county, the remains 

 of Holoptj^^chius have been found, but of its identity with the 

 Avestern species, or its relative position to known beds, we 

 have at present too little knowledge to form any satisfactory 

 conclusion. 



Notwithstanding that as early as 1839, I had recognized the 

 red sandstone with fish remains, as a distinct formation succeed- 

 ing the Chemung grouj) in the Tioga vallej^, and had observed a 

 series of essentially non-fossiliferous sandstones and conglom- 

 erates following it in regular succession, I afterwards became 

 doubtful of the i^ropriet}^ of retaining the distinctive term of 

 " groups" for these formations. This red sandstone soon thins 

 out, or is essentially merged, so that its distinctive features can- 

 not be traced far to the westward. In this condition of the rocks, 

 and the obscurity regarding the line of demarkation, the entire 

 series in southwestern New York and adjacent parts of Pennsyl- 

 vania, to the base of the coal conglomerate, has been usually 

 designated ' ' Chemung group. ' ' At the same time a series of rocks 

 in eastern Ohio, described in the original Ohio survey as the 

 " Waverly sandstone series," had been supposed to represent 

 the Chemung group ; and the shaly formation below, usually con- 

 sidered non-fossiliferous, was regarded as the continuation of the 

 Portage group. It was only when the fossils began to be more 

 critically studied that doubts were entertained of this reference 

 of the Ohio rocks. Dui-ing the study of the Braohiopoda of the 

 fourth volume of the PaUcontology of New York, I became satis- 

 fied of the necessity of separating, upon palseontological grounds 



