500 AxNALS OF THE Carnegie jNIuseu.m. 



include both limestone and shales. In describing the formation, these 

 three areas will be discussed separately. 



The Lake Cha.mpi.aix Region. 



As stated in the introduction, the work undertaken by the writer has 

 been purely paleontologic in character, and for the stratigraphy I have 

 followed the Chazy sections as described by Brainerd and Seely. In 

 the course of the work the sections at Chazy, Valcour Island, and 

 Crown Point have been remeasured and the results are within a few 

 feet of those reached earlier by Professors Brainerd and Seely. In 

 this place it seems better to give their synoptical tables than to pre- 

 sent the rather detailed sections prepared by the writer. For a de- 

 scription of the formation north of the Canadian boundary to Montreal, 

 the reports of Logan, Ells, and Ami are drawn upon (Geology of 

 Canada, 1863, and Reports of the Canadian Geological Survey, 1896 

 and 1899). 



In general the Chazy rocks are exposed along the western side of 

 Lake Champlain in a narrow belt running almost north and south 

 from Joliette, north of Montreal, to Orwell, Vermont. The belt in 

 which these rocks occur is seldom more than ten miles wide, and is not 

 a continuous exposure, but the formation occurs in small patches, in 

 most cases evidently fault blocks, and the strata are usually inclined at 

 a considerable angle. The most frecjuent dip is northeast, but there 

 are many places where the dip is northwest or west. There are some 

 places where the rocks are perfectly horizontal, but these regions are 

 of small extent. 



The principal outcrops are along the west side of Lake Champlain 

 and on the islands in the northern part of the lake. South of Wills- 

 boro Point there are scattered patches on both sides of the lake nearly 

 to Fort Ticonderoga, the most southern exposure on the west side being 

 about ten miles north of that place. On the eastern side the most 

 southern outcrop of all is at Orwell, five or six miles east of the lake. 

 The description of the section at Chazy will be given first, and then 

 other prominent localities in their order, going southward. 



77/^ Chazy Section. 



In the ty])e section at Chazy the base of the formations is not 

 shown. Brainerd and Seely divided the formation into three divi- 

 sions, A, B, and C, which are in order the Lower, Middle, and Upper 

 Chazv. 



