Trans, N. Y. Ae. Sct. - 26 LVov. 14, 
observation, viz., that two glacier streams have swept over these moun- 
tains, the Continental Glacier from the N. W., submerging and carving 
out the highest peaks, and the Hudson Valley Glacier from the N., 
later, more shallow, bearing along vast quantities of materials derived 
from the crystalline and lower Silurian rocks of the Adirondacks and 
of the Helderberg Mts., and strewing the whole region with their 
boulders; and that no local glaciers have existed in the Catskills after 
the retreat of the Hudson Valley Glacier. 
Tilting of the Catskill plateau.—In the previous paper an explana- 
tion had been given of certain facts which seemed to indicate that the 
whole formation had been gently inclined to the East and then to the 
Southeast, before assuming its present W. N. W. inclination, at a 
period far anterior to the Glacial epoch. A profile section of the 
ancient Kaaterskill valley was exhibited, reaching from Haines’ Falls 
nearly to the junction of the N. and S. branches of Schoharie creek, 
proving the gentleness of the slope, the absence of rock, and the exis- 
tence of a deep and narrow buried cafion, now filled up with moraine 
material and a capping of peat. 
A comparison of the altitudes of Prattsville (1164 ft.), a point on the 
Western axis, 12 miles distant from the Kaaterskill Clove, and of the 
lip of the stratum above Haines’ Falls (1857 ft.), at the head of the 
Clove, shows that a depression of the latter point below a line connect- 
ing these two points, even to the extent of a single degree, would cause 
a descent of nearly 700 feet from Prattsville to Haines’ Falls, z. ¢., 
toward the East. The excavation of the deep Kaatersk']] and Plaater- 
kill Cloves could hardly have been effected by the small streams now 
occupying their beds. It is more probable that the Schoharie creek for- 
merly flowed, at a higher level, to the eastward into the Kaaterskill Clove, 
and afterwards toward the south-east into the Plaaterkill Clove, before 
the latest tilting of the plateau to the W. N. W. caused a reversal of the 
flow of the stream, in the very opposite direction, through the greater 
part of the same valley. An objection to this theory presented itself 
in the obstacle which has created a turn to the S. W. in the North 
branch of Schoharie creek, near its junction with the South branch. 
But on recent examination th s was found to consist not of rock but of 
a huge mass of coarse moraine material, deposited during the Glacial 
period on the southern slope of the Schcharie valley. 
Sculpture of the plateau.—In a terrane consisting of strata which 
dip at varying and perhaps very high angles, the carving out of ranges 
and production of ravines and gaps may generally be assigned to the 
occurrence of flexures, of dykes or faults, or of beds whose material is 
unusually soft, fragile, or rich in minerals of easy decomposition. But 
the problem of topographical sculpture is less easily solved in a stratum 
