212 Glaciation of Mountains^ etc. — W. UjpJiam. 
Ottawa basin farther north. He also notes strise bearing S. E. 
on Mt. Anthony in Saratoga county.* 
In New Jersey professor John C. Smock's observations 
show that the ice-sheet covered the highest point of the state, 
which lies near its most northern angle, at an elevation of 
1,804 feet. Its distance north from the terminal moraine is 
about thirty-one miles. The New York highlands and the 
Shunemunk and Shawangunk mountains are also glaciated 
to their crests. But in the Catskill mountains professor 
Smock finds that the glacial drift and strife extend upward 
only to an elevation approximately 3,000 feet above the sea.^ 
Their limit is thus a thousand feet below the highest summits, 
Slide mountain, the culminating point of this group, having, 
according to professor Guyot's determination, an altitude of 
4,205 feet. The distance from Slide mountain south to the 
terminal moraine on Staten island at the sea level is a 
hundred and five miles. The ice sheet in this distance had 
an average slope of nearly thirty feet per mile, or slightly 
less than a third of a degree ; and large areas of the Catskills 
rose above its surface at its time of maximum thickness and 
extent. 
Professor Smock writes : "The amount of erosion in the 
Catskills has been very great, since the strata [sandstones 
and shales] are nearly everywhere horizontal, or inclined but 
a few degrees from the horizon. The main valleys appear to 
have been eroded prior to the glacial epoch, and the existing 
features were largely determined by the long-continued wear 
of preglacial waters ; so that the ice-sheet did little beyond 
filling partly some of the valleys and abrading the more 
prominent of the lower ridges. The valleys are essentially of 
erosive origin, obscured, however, now by glacial debris in 
many places. In some of them, as that of the Batavia Kill in 
Windham, the Stony Clove and Woodland Valley, there are 
very plainly marked moraines, indicating the existence and 
retreat of local glaciers. The larger valleys of the Schoharie 
Kill, the east branch of the Delaware, and the Esopus creek, 
also have their moraines, though not so well defined. Subse- 
quent to the retreat of the great mass of the continental 
glacier, these valleys were no doubt occupied by detached 
^American Journal of Science, III, 1873, vol vi. 
«Ibid., 1883, vol xxv. 
