114 NEW YORK STATE MUSEUM 



more frequently from the Lowville limestone; and prevailingly 

 from extremely fossiliferous black and gray limestone beds which 

 are of lower or lowest Trenton age. 



5 A specially interesting feature of the fauna of these Trenton 

 pebbles was found in the considerable number of new forms, 

 largely braehipods, trilobites and ostracodes. Some of these 

 belong to genera new to the American Trenton but well repre- 

 sented by very similar forms in equivalent north European 

 beds. These, as well as several other forms which also occur 

 in the Kysedorph hill conglomerate and are restricted to the 

 eastern Trenton, support the conclusion derived from the distri- 

 bution of the Normans kill graptolite shales, viz that in lower 

 Trenton time the eastern Trenton sea had attained connection 

 with the Atlantic. 



6 As the fauna of the Trenton pebbles is in marked features 

 different from that of the beds known in the Mohawk and Hud- 

 son valleys, it is supposed that the material was derived from 

 the regions to the east and northeast, where the Trenton beds 

 have now become metamorphosed and the fossils obliterated. 



7 The occurrence of the lower Trenton limestone pebbles in 

 this region is taken to indicate that at the beginning of the Tren- 

 ton period the quiet limestone-depositing Trenton sea extended 

 also over this region; while the presence of the Normans kill shale 

 of lower Trenton age proves that this favorable condition soon 

 came to an end, and a radical change in the physical conditions 

 took place. 



8 The conglomerate itself is intraformational. It is embedded 

 in shale of the same age, and the fauna of the matrix of the 

 conglomerate is of lower Trenton age. The conglomerate, there- 

 fore, evidently does not mairk any important change in the physi- 

 cal conditions of the region, but is probably due to a temporary ele- 

 vation of a low Appalachian ridge into the sphere of wave action. 



