GEOLOGY OF THE LAKE PLACID REGION 59 



the gorge of the East Branch a mile south of Keene Center. No 

 doubt additional ones will be discovered b}^ observation of the 

 brook bottoms and the writer would be glad to be informed of 

 any that may be met. 



Moraines. The moraines of unsorted sand and boulders are 

 the most striking evidence of the glacial period. They meet the 

 eye of the visitor immediately on reaching Lake Placid, because 

 the town is built upon a ridge formed of them. Huge boulders 

 project from the sides of cuttings wherever the highways have 

 been graded. This commingling of large rocks and fine sands 

 will appeal even to the unscientific observer as only to be ex- 

 plained by the work of ice. This particular moraine is an im- 

 portant one because Lake Placid is the result of it. Like a great 

 dam the glacial drift confines the water to the valley between 

 the hills, while Mirror lake is in a depression in the dam itself. 



Other moraines are not lacking in the region but as our obser- 

 vations are as yet too incomplete to accurately map them no dis- 

 tinction is made on the map. Some minor points of interest may 

 however be mentioned. In the pass toward French's at the 

 north end of Lake Placid, and beyond Eagle Eyrie, there is a 

 huge boulder that is 25 x 20 x 15 feet, as determined by pacing. 

 It stands by itself in the forest. Others of notable size are 

 abundant on the hillsides south of Keene Center. The boulder 

 at John Brown's grave is one of the sights familiar to the Lake 

 Placid summer visitor. 



The boulders in the moraines are chiefly the hard crystalline 

 rocks already described. Occasionally one finds a fragment of 

 Potsdam sandstone, that must have journeyed in from many 

 miles to the north. 



Water-sorted sands and gravels. These consist of pebbles 

 and sand in a more or less clearly stratified condition. They 

 lend specially to form level plains and fan shaped terraces. The 

 plains appear to be abandoned lake bottoms, while the terraces 

 are the deltas which entering streams built up in the former 

 lakes. The deltas occur opposite the tributary valleys and 



