No. 161.] 
119 
Saranac river and Lake Champlain, the whole length of which it 
skirts, with perhaps a few places where the primitive rocks ex- 
tend into it. The western edge or margin of this sandstone, is 
about 12 miles west of Lake Champlain, towards Redford, on the 
Saranac. If a line is now drawn from Redford to Malone, it will 
pass nearly along its northeastern margin. If another line is now 
drawn to Hopkinton, it will mark its limits in that direction. — 
Malone is, therefore, the point farthest north at which the primi- 
tive rocks occur in this district. This rock dips, in the south part 
of Champlain to the northeast. In other places it is horizontal, and 
in others again is raised by the primitive rocks, on which it always 
rests, so as to give a very large angle. It is also occasionally 
much contorted, and of a red colour when near the primitive beds. 
This rock, so far as yet appears, is destitute of metalliferous be'ds. 
It contains occasionally a few simple minerals, but they are most- 
ly those confined to the calciferous variety. 
Superimposed upon the rock last described, is the transition 
limestone, or as it is sometimes called, blue limestone. Its colors 
vary from light gray to a dark blue. Its structure is generally 
compact, and breaks with a slightly uneven surface. Its upper lay- 
ers are usually much weathered and broken, so that frequently, to the 
depth of 10 feet or more, they present a stratification composed of 
rounded blocks, more or less detached or separated from each 
other. They are also deeply fissured or cracked, and in many 
places streams, in passing over these beds, penetrate these open 
places and are lost; and after pursuing an underground course, for a 
time, emerge again to the open day. The streams during their 
confinement below, often wear deep and wide caverns; hence this 
limestone is sometimes called cavernous limestone. Something of 
the extent of this limestone in the northern counties, may be 
learned from the following account of it. It appears along the 
margins of Lakes George and Champlain. In the vicinity of Platts- 
burgh it is 5 or 6 miles wide and dips about 10° to the east. In 
Chazy it is 9 miles wide; three or four miles farther north, it is 
only 4 miles , with an easterly dip, varying from 10° to 15°. At 
Champlain again it is about 3 miles. In going from Champlain to 
St. Regis, a distance of 65 miles, we passed over 3 miles of lime- 
stone; then for 45 miles, to Westville, sandstone; then from West- 
ville to St. Regis, 16 miles, limestone, with a dip of 5° to the N. 
E. and sometimes to the N. W. On the St. Lawrence it is 4 or 5 
miles wide up to the vicinity of Ogdensburgh; then to the Thou- 
