538 NEW YORK STATE MUSEUM 



Port Kent 

 On the shore of Lake Champlain at Port Kent is a small 

 exposure of the Potsdam sandstone, 124-A1. It is almost 1 mile 

 north of the anorthosite of Trembleau mountain which juts out 

 for some distance into the lake south of Port Kent station. 

 The rock here is 20 feet thick and consists of heavy and thinly 

 bedded layers of white and gray sandstone, some of which con- 

 tain thin seams of black pebbles. Ripple-marks are common. 

 No fossils. The rock is much broken by joints and the layers 

 are bent; indications of proximity to a line of disturbance. 

 These beds do not belong to the basal portion of the formation, 

 and must be separated from the anorthosite by a fault. 



Ausable river section from Keeseville through Ausable chasm 

 Near the road 1 mile west of Keeseville, just beyond the race- 

 track, the base of the Potsdam sandstone, 150-E2, is seen lying 

 in a depression between two ridges of anorthosite. The actual 

 basal contact of the sandstone can not be seen. This locality 

 was described in considerable detail by Gushing 1 in his re- 

 port on Clinton county. The rock is here a coarse con- 

 glomerate of red sandstone containing gneissic fragments at the 

 base, overlain by red sandstone of finer grain. The rock through- 

 out the entire exposure contains a large amount of feldspar. 

 Across the strike to the southeast the nearest exposure of the 

 sandstone is on the bank of the Ausable river, about \ mile 

 above Keeseville, where it, 150-B1, outcrops in the vicinity of a 

 boss of anorthosite on the right bank. This outcrop was men- 

 tioned by Walcott (1891, p. 343), and was evidently considered 

 by him the basal portion of the sandstone. In reality it is an 

 exposure along a fault which separates it from the anorthosite, 

 and the rock here belongs to a horizon quite well up in the for- 

 mation though just how far it is impossible to say. 



From this point the sandstone is exposed at intervals for If 

 miles to the dam of the pulp mill at Alice Falls, a short dis- 

 tance above the head of the Ausable chasm. Throughout this" 

 distance the beds exposed, 150-B1 to 7, are of the same char- 

 acter as those of the lower portion, 125-B1 to 2, and Al, of the 



J N. Y. state geol. 15th an. rep't 1895. p. 548. 



