EXPLANATION OF THE PLATES. 
PLATE I. 
It is designed to represent the valley of the Hudson at Albany, and the Helderberg range as it appears 
from the high grounds in the rear of Greenbush. The valley is colored yellow,, and is a narrow 
alluvial formation reposing upon the tertiary or Albany clay. The immediate rock, and which 
appears at the Norman’s kill, is the thick -bedded gray sandstone of the superior part of the Hudson 
river group ; it extends nearly eight miles west, before it disappears beneath the calcareous shales 
of the waterlimes at the base of the Helderberg hills. The group which forms the Helderberg 
division appears in succession, and makes by itself a full and complete series, which ends with the 
Onondaga limestone at New-Scotland. The superior part of the Helderberg range, as represented in 
the panoramic view, is the Erie division. Upon the extreme left is the Catskill or Devonian division, 
which is colored red. The Pentamerus and Delthyris shale crop out at the main terrace on the 
right, and dip to the southwest. Still farther upon the right the Hudson river group, the thick- 
bedded sandstone, interlaminated with a black slate, forms the slope as it extends itself towards the 
Mohawk valley. The view is north and south. The lowest rocks belong to the Champlain 
division, the upper to the Catskill. The Ontario division is wanting in the series. 
PLATE II. 
The view is designed to exhibit some of the features of the Mohawk valley, particularly its vegetation. 
The elm, with its pendulous branches and small and numerous ones upon the trunk, has the com¬ 
mon shape and condition of the red elm of this valley. 
PLATE III. 
The country about Rochester is richly exhibited from Mount Hope. The view looks toward the north¬ 
west. It is in Central New-York, and upon the argillaceous or wheat soils, that the splendid 
American elms flourish and attain a great height. They often appear without branches or limbs, 
until the trunk spreads as it were at once into a noble head. They form characteristic points in the 
landscape. 
PLATE IV. 
The Catskill creek, for four or five miles, forces its way through a region excessively disturbed: it is 
in fact a part of the great north and south fracture, in which insulated hills often appear, but still 
formed of rocks which seem have been forced upward and broken from the adjacent strata. This 
mass of Pentamerus rock forms a part of a segment of a great curve, the edges of which dip towards 
the centre. The inferior, the Hudson river group, is the lowest mass, and dips rapidly beneath the 
limestones. 
PLATE V. 
The panoramic view was taken from the northwest extremity of the Helderberg range, the observer 
looking east. The valley of the Hudson occupies the extreme of the middle grounds, the river 
itself appearing only at intervals. The foreground is occupied by the limestones of the Helderberg. 
The long narrow hills, with their narrow intervening vallies, appear in the hack ground ; but the 
distance is too great to exhibit their characteristics. 
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