410 PROCEEDINGS OP WASHINGTON MEETING. 



west, and in at least one place it entirely encircles an outlying hill of gabbro.* 

 In this region the contacts have been studied by H. P. Cushing, whose inferences 

 are in general very much like those of the writer. 



Willsboro- Essex Embayment 



Southward along lake Champlain, in the townships of Willsboro and Essex, the 

 Potsdam and Ordovician sediments make a pronounced embayment in the bight 

 north of Split Rock mountain. The Potsdam sandstone extends farthest inland 

 and is present on both sides of the Bouquet river as far south as Whallonsburgh. 

 It reaches 300 feet above tide (200 feet above Lake Champlain) and lies very flat, 

 the dip being but 10 degrees. By comparison of the geological maps of Willsboro 

 and Essex f with the Willsboro atlas sheet of the U. S. Geological Survey, the re- 

 lations appear very distinctly. 



Westport Embayment 



Still farther south beyond the ridge of the Split Rock range, the Paleozoics set 

 up in a deep bay at Westport $ and reach the 300-foot contour. They extend seven 

 miles southward, and at the latter extreme reach the 400-foot contour. Some 

 three miles of gabbro and crystalline limestone then form the shore until at Port 

 Henry the Potsdam is again met. The maximum width of the Paleozoics in the 

 Westport embayment is about two miles. They embrace strata from the Potsdam 

 to the Trenton. 



Port Henry Embayment 



At Port Henry another embayment of Potsdam with a little faulted Calciferous 

 comes in and runs up to the southwest to an altitude of over 600 feet above tide. 

 It lies on the north side of Bulwagga mountain, but has a quite flat dip. 



Resume 



In all the cases hitherto cited faulting no doubt plays a considerable part, and 

 the ever-present glacial drift quite generally masks the actual contacts, but none 

 the less there is no doubt that early Cambrian or pre-Cambrian depressions deter- 

 mined in large part the locations of the areas of deposition. The following cases 

 are, however, more significant. 



Crown Point-Schroon Lake Embayment 



On the south side of the embayment at Port Henry, Bulwagga mountain, as 

 stated, closes in and forms at the same time the northern boundary of the valley 

 in which is the village and most of the township of Crown Point. § The accom- 

 panying map, plate 51, figure 1, has been prepared by tracing off the 100-foot con- 



* See the geological maps of New York, to which reference has just been made. 



t'f. G. White : The Geology of Willsboro and Essex Townships, Essex County, N. Y. ; Trans- 

 actions N. Y. Acad. Sci., vol. xiii, p. 214, plate vi. J. F. Kemp : Preliminary Report on the 

 Geology of Essex County, N. Y. ; Kept, of N. Y. State Geologist for 1893, pp. 460-462. 



X See map of Moriah and Westport townships, by J. F. Kemp, in the Bulletin of the New York 

 State Museum, vol. iii, number 14. plate i. 



§ For a small geological map of Crown Point township, see writer's Report on the Geology of 

 Essex County, just referred to, p. 456. 



