10 Twenty-fourth Report on the State Museum. 



Dr. J. W. Hall and Mr. G-. B. Simpson have been temporarily 

 employed as field assistants in tracing the outcrop of tliis formation, 

 and collecting fossils from it and from the rocks above and below. The 

 result has very clearly demonstrated what I had before suggested, 

 that the rocks in many localities of the south-eastern counties of 'New 

 York hitherto referred to the Chemung group, with specimens there- 

 from incorporated in the collections of the museum, do. really belong to 

 the Hamilton group, and contain the characteristic fossils of the latter. 

 The difficulties attending the determination of the limits of the 

 formation referred to the Catskill group are still far from being 

 resolved. The suggestion made by some geologists, that the foiTua- 

 tion probably does not exist within the limits of the State, has, 

 however, been abundantly disproved. 



The results of the investigations have given us the limits of the 

 formations, as traced in Otsego, Chenango and the western part of 

 Delaware counties, together with large collections from the Hamilton 

 and Chemung groups, as well as from the Oneonta Sandstone. Of 

 the latter, we had not before a satisfactory collection of authentic 

 specimens in the State Museum. 



The investigations have likewise been continued in the south- 

 western counties of the State, and adjacent parts of Pennsylvania, 

 with reference to the relations of some of the conglomerates to the 

 Chemung group, and the overlying Red Sandstone. 



In the original collections of the geological survey, some of the 

 conglomerates of the southern counties, containing certain fossils, 

 were referred to and arranged with the Chemung group, while those 

 from other localities but without fossils, were referred to carboni- 

 ferous age. This latter reference arose from finding some ferruginous 

 beds, supposed to be the outliers of the Red Sandstone of Tioga, 

 near the summits of some of the hills, and below the conglomerates. 

 These have since been proved by their contained fossils to belong to 

 the Chemung group, and it has not yet been demonstrated, that the 

 Red Sandstone of the adjacent part of Pennsylvania, does occur 

 within the limits of the south-western counties of New York. 



To a very great extent, the conglomerates have been ascertained 

 to belong to the Chemung group, and to contain numerous character- 

 istic fossils of the formation, while in some localities, at least two 

 hundred feet of shales and shaly sandstones, charged with Chemung 

 fossils, lie above the conglomerate. So many localities have now been 

 examined, that we may conclude that all the conglomerates of the 



