1 1 8 
INTRODUCTORY. 
tain any impression of the chance explorer or, perhaps, never invaded 
by the foot of man. remains rugged and absolute as it came from the 
cosmic forces. 
The entire region is decidedly mountainous, and traversed by 
numerous valleys, of greater or less extent, with their streams and 
brooks all swiftly flowing over rough and stony beds. The main 
water-course of that part ol the region here considered is Esopus 
Creek, which, rising in one branch (Birch Creek) almost at a point of 
junction of three counties — Ulster, Delaware, and Greene — circuit- 
ously traverses the former towards the Hudson, which it finally 
reaches, after a journey ol nearly sixty miles, at a point not thirty 
miles from its source. 
The railroad follows the course of this stream on its track through 
the mountains, and that the birds have also taken advantage of this 
unobstructed way from the Hudson to the heart of the Catskills seems 
to be shown by the presence of several species along the valley, even 
far in the mountains, which were not noticed without its limits. 
Extending from this valley, less than thirty miles from the Hudson, 
is the Big Indian Valley or Hollow, which passes irregularly south- 
ward with a gradually increasing elevation until dissipated in moun- 
tain passes, about eight miles from its entrance. Here it cradles the 
early flow of the main branch of Esopus Creek, guiding its rapid and 
increasing waters into more expansive course below. 
The highest elevations in the Catskills are found among the moun- 
tains about this point, where are clustered several peaks closely 
approaching four thousand feet in altitude. Rising among these is 
Slide Mountain (4,205 feet), which has recently been ascertained to 
exceed in height all other peaks of the Catskill group, so that to this 
comparatively unknown mountain has now been awarded the palm 
which was long supposed to belong to others. Its name was evident- 
ly bestowed with reference to an extensive land slide which has bared 
its eastern slope, for a varying width of rods, from near the summit 
far down into a gorge, where, from above, its devastation becomes 
