8TEVENS, GLACIATION OF OVERLOOK MOUNTAIN 263 



example of the extent to which the direction of the ice near the surface 

 can be affected by the topography. A variation of more than ninety 

 degrees in the direction of the motion of the ice is indicated by the striae 

 on Overlook itself. Just northeast of Overlook, the course of the glacier 

 was nearly south (S. 20° W.). A portion of it, however, flowed over the 

 ridge between the Plattekill and Overlook Mountains and through what 

 is now the upper valley of the Saw Kill in an almost westerly direction, 

 moving nearly southward again through Meads Gap and at Shady. The 

 ice moved almost directly west up the "Woodstock Valley, its course be- 

 coming gradually more southerly as it passed over the group of low hills, 

 known as the Ohio Mountain, 4 and the region farther south (S. 60° W. 

 near Glenford and S. 40° W. at West Hurley). 



Moraines 



While glacial action has probably not greatly altered the general out- 

 lines of the mountain, the valleys have been more or less filled with gla- 

 cial deposits. A moraine nearly a mile long fills much of what was once 

 the much deeper valley south of Meads Gap; while the upper valley of 

 the Saw Kill, between Overlook and the mountain ridge to the north, is 

 filled to a considerable depth with morainic material. Both of these are^ 

 in reality, parts of a large moraine which extends westward from Over- 

 look. 



As the moraines of the Catskills have been but little studied, a brief" 

 account of the material composing them may be of interest. About 

 eighty per cent of it is of local origin, consisting of the sandstone, shale 

 and conglomerate found throughout the Catskills. Of these materials, 

 conglomerate is the least common and forms less than ten per cent of the 

 whole. About one-half the local material consists of bowlders of various 

 sizes, with which pebbles and gravel are mixed with no sign of stratifica- 

 tion. From this it is apparent that water has played no part in the 

 deposition. 



The foreign material consists largely of quartz and several kinds of 

 granite, with occasional pieces of water-worn, stratified rock and some 

 sandstone containing brachiopodous shells. Some shells picked up in 

 the bed of the Saw Kill, about two miles from its source, have been iden- 

 tified as Spirifer arrectus, 5 a species characteristic of the Oriskany sand- 



*This mountain is called "Tontshi Mt." on the TJ. S. G. S. topographic sheet. It 

 seems, however, that this must be an error, as this elevation is locally known only as 

 "Ohio Mt." ; while the name "Tontshi" is applied to the much higher peak, left un- 

 named on the government map, just east of Ticetonik. 



5 The writer is indebted to Professor Charles Schuchert of Yale University for the 

 identification of this specimen. 



