186 Account of the Geology, Mineralogy, Scenery, &c. 
thern side to Kedidika Hook ; it there takes a northwest — 
direction parallel with the river ‘for four miles, rising abrupt- 
ly from the water to a great height ; its ledges in many 
places precipitous are composed of the materials observed 
in the Palisado rock, with the addition in some parts of 
the summit of a little sulphur rendering it friable. ‘The 
mountain is underlaid by sandstone, marking its secondary 
origin. At Haverstraw the chain rises to its greatest height, 
presenting numerous ledges and irregular elevations. ‘The 
most lofty peak called High Tower situated near Hav- 
erstraw landing, was found by Capt. Partridge to rise 850 
feet above the bed of the Hudson; a wall of rock of some hun- 
dred feet perpendicular height borders-the summit. Sand- 
sione in place is found onthe side and at the base of the moun- 
tain. Piles of dark angular blocks of greenstone in many pla- 
ces occupy the sides of the mountain to the exclusion of ve- 
getation. Puddingstone, containing smooth round pebbles 
is frequently observed. From Haverstraw the greenstone 
mountain ranges in a western course and sweeps with a di- 
minished height to the vicinity of the Highlands, presenting to 
the eye a profile of wild and irregular eminences. Iron is 
abundant in this western chain; frente of this ore of the 
best quality have been found in several places running from 
the North-River to the Highlands. The quality of many 
beds rich in iron is injured by sulphur. A manufacture of 
copperas from the sulphuret of iron met with in this sec- 
tion of Rockland county was once contemplated. Rich 
copper ore has been found not far from High Tower, but 
the traces of it are lost. On the southern side of the 
mountain running west from Haverstraw, the descent is in- 
general gradual ; much of the surface is cleared and culti- 
vated and of a medium soil, well watered by numerous 
springs ; large rolled masses of granite and gneiss rest on 
the mountain side, probably conveyed to this secondary re- 
gion from the Highlands by some convulsion of nature.— 
Pectanites and other marine petrifactions have been found 
on this ridge at considerable elevations ; fine grained trap 
is met with at the base. 
Westward of the Kedidica Hook range, and half a mile 
from the Hudson is situated a mountain lake four miles in 
circumference, called Rockland lake ;—-its surface is 150 
feet above the bed of the river from which it is separated 
