CHAMPLAIN CLAYS. 157 



of the St. Lawrence to the extreme southern Atlantic States, generally at a less elevation. 

 Because these fossils were found so abundantly in the valley of the St. Lawrence, the 

 deposits were termed Lawrentian deposits, by M. Dcsor. The same designation has been 

 applied by Sir W. E. Logan, of the Canada Geological Survey, to the oldest rocks found 

 upon the globe, the Hypozoic. As the former sense of the term Lawrentian is now mostly 

 obsolete, we shall use in its stead in this Report, the name Champlain Clays, a name which 

 has already been used somewhat. 



The extent of the Champlain Clays in Vermont is designated upon the Map, Plate II. 

 They are widest in Chittenden and Addison Counties, and may be found anywhere in the 

 Champlain valley below a determinate level, say 500 feet above the ocean. 



Many of the facts we have derived from the labors of our predecessors, not having 

 gathered many additions to their observations. We refer in particular to the Second 

 Report of Prof. Adams, where there are four pages devoted to these deposits, which are 

 called Older Pleistocene. His facts are of unusual interest, because of his great knowledge 

 of the habits and nomenclature of shells. He describes the deposits of this group in their 

 order of position, as follows : 



" 2. Brown clay, fine sand, and loose gravel. 



" 1. Blue clay. 



" The first three cannot be arranged in a universal order of superposition ; the brown 

 clay and fine sand appear to be for the most part local equivalents, and the gravel is vari- 

 ously interstratified with, or overlying either. The blue clay appears, in the innumerable 

 examples of junction with the other deposits, to occupy the lower place, although it is by 

 no means certain that all the blue clays of this period are contemporaneous, and anterior 

 to all the brown clay and sand. Yet such would seem generally to be the fact. It is 

 scarcely necessary to remark, that there are some clays, as well as many sand deposits, 

 which owe their present situation to agencies of a date much more recent, or even of the 

 historical period." 



In describing the deposits upon the Winooski River near Burlington, we said that the 

 sand was found overlying the clay. It is a general fact throughout the State upon the 

 rivers, that in the higher terraces the sand is above the clay. Numerous sections in other 

 States show the same thing. But these are fluviatile rather than oceanic deposits. It is 

 true that the materials were brought down by rivers from the mountains, but they must 

 have been deposited in the ocean to form such a level surface, and in this sense they may 

 be said to be marine. Else, where did the whole of the clay in this deposit originate ? 

 The ocean cannot produce clay, it deposits the finely suspended materials that have been 

 brought within its reach by rivers. The heavier deposits may have been deposited near 

 the mouths of the rivers, while the finer matters have drifted to the south. Such seems 

 to have been the case in the Champlain valley, for the sand in FIO. no. 



the terraces is confined to the northern part of the deposits, and 

 near the mouths of the principal streams, while the clays are 

 found over Chittenden and Addison Counties to the south. At 

 the time, also, when this sea bottom deposit was accumulating, 

 a more 1'apid occasional current would have brought down gravel 

 and sand, which became interstratified with the clav in some & ' n 



i Seclion in New Haven. 



places. 



