AMERICAN JOURNAL OF SCIENCE. 
[THIRD SERIES.] 
Art. LVIL—On the Physical Structure and Hypsometry of the 
Caiskill Mountain Region; by ARNOLD Guyot, Princeton, 
New Jersey. 
IN a former paper on the physical structure of the Appala- 
chian system, I noted the fact that, though extending through 
the most populated and civilized part of the United States, that 
system of mountains was still among the least known of our 
country. This remark applies with double force to the Catskill 
Mountain region. 
Situated in the old and flourishing State of New York, only 
one hundred miles from its Sania in full sight and within 
a few miles of the great artery of travel, the Hudson River; 
visited every summer by thousands of tourists in search of the 
eauties of nature and of the cool air of its high valleys and 
plateaus, its real mountain region has been thus far almost a 
sealed book to the geographer and the geologist as well as to 
the transient visitor. It seems a matter of legitimate surprise 
that to this day no physical map of the Catskills, deserving the 
‘i True, there are county and township 
maps which trace with tolerable accuracy the water courses, 
the roads, the villages and the scattered farms; but they all 
end with the cultivated portions of the valleys and leave the 
mountains either in blank or give them in very inaccurate and 
unintelligible outlines. 
For one, however, who has visited that part of the country, 
with the view of studying its physical conformation, the cause 
of the sad condition of its cartography is no mystery. The 
whole region was originally an unbroken forest, and, with the 
Am. Jour. Sct.—Tuirp _— Vou. XIX, No. 114.—Junz, 1880, 
