216 
GEOLOGY OF THE SECOND DISTRICT. 
small shrubs to take root and grow. At the lower part of the mountain, the width of this 
gorge or chasm is about eighty feet, which is the width of the dyke, the whole of which is 
removed up to the walls upon each side. The materials which have been swept out of this 
gorge are in confused heaps below, and help to fill up the chasm between the mountains, in 
which the Avalanche lake is situated. Besides the immense quantity of materials from the 
dyke, consisting of rocks, earth and trees, a great slide, extending also from the top to the 
base of the mountain, contributes largely to the loose materials in this narrow pass. Great 
quantities of apparently pulverized vegetable matter are deposited in this lake, at least along 
the shores. That part of the gorge nearest the lake is steep and difficult of ascent, and also 
the deepest; while in ascending the more distant part, the inclination is found to be less, but 
the space above is crowded with large rocks which have been moved from their beds, some 
of which are fifty feet in length, and all have commenced their journey to the region below. 
Upon the west side of Avalanche lake. Mount McIntyre rises in a mural precipice of one 
or two hundred feet; in the face of which, the dyke which bisects the opposite mountain dis¬ 
tinctly appears. After going up three or four hundred feet of this latter mountain, the dyke 
can be traced up by the eye to near the summit of Mount McIntyre, by two parallel cracks 
or fissures, which appear from this distance about two feet wide. Upon this mountain there 
is a great deficiency of water, and there is no stream pouring down upon this face of it; and 
from this cause, the dyke is not broken up as on the opposite side. A small stream flowing 
into the cracks and fissures would break up this mass entirely ; while freezing and expanding 
would first separate, and then force down the masses into the chasm below. 
The dyke consists of the rock denominated sienite, or hornblende and granular feldspar. 
In the midst of the Sandford ore bed, the same rock appears, and which I found in three or 
foixr places, though the great m.ass of the mountain in which this ore occurs is the ordinary 
hypersthene rock. 
The view which I have given of this dyke is strictly a map, or it is a perfect transcript of 
it as it was when the view was taken ; but great changes are taking place from year to year, 
and a view which is literally correct to-day may not be so to-morrow. One half of the mural 
precipice which appears in the sketch, may tumble down in an instant. 
Adirondack Pass. 
In the midst of the mountains of Essex county, at the source of one of the main branches of 
the Hudson river, there is a deep narrow gorge, which has been denominated the Adirondack 
Pass. In its general character, it is in keeping with what appears on all sides where this 
fcldspathic mass is the predominant rock, except that the scale on which this gorge has been 
formed is far larger and more magnificent. 
This pass may be approached in two directions : First, from the Adirondack iron-works, 
from which it is distant about five miles. In this route, the aforesaid branch of the Hudson is 
followed up the whole distance, even to its source, which will be found at the very base of the 
