Note. — In the earlier pages of this volume, printed in 1862, a few species of the 

 genera Linqula and Discina were described from the Waverly sandstones of Ohio, there 

 having been at that time no sufficiently well marked limit established between the western 

 extension of the Chemung Group and these beds. Farther comparison of species of other 

 genera led to a doubt of the propriety of uniting these formations on zoological considera- 

 tions alone, and some species from the Ohio formation, previously described by me, as well 

 as others at that time under investigation, were omitted from the volume for this reason. 

 It is true, however, that certain species found in the Waverly sandstones and associated rocks 

 of Eastern Ohio, are apparently identical with forms occurring in the Hamilton and Chemung 

 Groups of New York ; but these are comparatively so few, that their recurrence can only 

 be regarded as due to a repetition of the same or similar physical conditions in the two or 

 more epochs. 



At a later period, I have compared the moUuscan fauna of the Waverly sandstones with 

 that of some of the conglomerates, at or near the summit of the Chemung Group in Alle- 

 gany county, New York, and the adjacent parts of Pennsylvania, which contain numerous 

 lamellibranchiate shells. But in all these cases a farther investigation has proved the 

 occurrence of Spirifera Vemeuilii, a characteristic fossil of the Chemung Group in the same 

 association, while the lamellibranchiate forms, with few exceptions, are altogether of distinct 

 species. In the collections of the Geological survey these fossiliferous conglomerates were 

 arranged as a part of the Chemung Group, while the coarser non-fossiliferous rocks of sim- 

 ilar character in Allegany and Cattaraugus counties were considered as outliers of the car- 

 boniferous conglomerate. We have since learned, however, that the conglomerate of the 

 southwestern counties of the State is a constituent member of the Chemung Group. The 

 red shaly and arenaceous strata, sometimes observed beneath the conglomerate, are merely 

 subordinate beds of little significance and in no way related to the red rocks of the Catskill 

 Oroup, to which they have sometimes been referred. The red sandstone, or fine conglom- 

 erate, sometimes becoming an impure iron ore, which at one time was referred to as the 

 probable attenuate extension of the red sandstone of Tioga, belongs, for the most part or 

 entirely, to the Chemung Group. 



From late investigations in the Geological Survey of Ohio, Dr. Newberry has shown 

 that the beds containing Spirifera Vemeuilii do actually pass beneath all the strata bearing 

 the characteristic fossils of the Waverly sandstones, and are separated from them by a 

 black shale. This position established, puts at rest any doubts as to the relation of these 

 beds, and until wo possessed some ascertained fact of this kind, all discussion upon the ques- 

 tion could lead to no definite result. 



