Kemp — Geology ok Essex County. 



599 



all through the gneiss is remarkable. We can only infer that the intrusion 

 of the larger ones extensively shattered the walls and that the molten trap 

 oozed into every notable crevice. The rock is a diabase. The presence of 

 the gabbro across the lake at No. 73 may be remarked, but I see no reason 

 to connect the two. A very similar group of little dikes was also met west 

 of Schroon Lake post office at No. 83. The accompanying sketch ( Figure 2) 

 illustrates their relations. The exposure was only a small one, eight or ten 

 feet square, and the tiny dikes were faulted in an interesting way, as shown 

 in the figure. The smallest of these was doubtless originally continuous 



Figure 1. 



Series VI. The glacial drift is very generally present, and, as already 

 remarked under kSeries III, enormous boulders are of great abundance just 

 south from the mountains. The town, however, seems to have been in the 

 region of transportation rather than of deposition, and the hills of gravel, 

 moraines, etc., that we meet farther south are lacking. Water-sorted sands 

 of post-glacial times are present in the stream valleys. The hills are of rock 

 so far as observed, and the boulders noted were doubtless stranded in the 

 melting of the ice sheet while they were in transit. All the large boulders 

 are anorthosites. 



