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BASALTIC ROCKS. 
rising in perpendicular height from 20 to 400 feet, 
and below the cascades it passes through a mount- 
ain of the same more than 1000 feet high, and 
nearly vertical. 
Extensive basaltic dikes exist in Essex county, 
in the northern part of the State of New- York, 
which pursue an easterly and westerly course to a 
great distance. At Avalanche Lake, a dike eighty 
feet wide cuts through Mount M'Martin nearly in 
its centre. Here we perceive on a large scale the 
effects of frost and water in breaking up the solid 
crust of the globe ; there being numerous masses 
of rocks, from 50 to 100 feet long, broken up from 
their original beds, and carried partly down the de- 
clivity, constituting a mass of ruins from the base 
to the summit, which the rains and frost are con- 
stantly reducing to smaller masses, and urging them 
onward to mingle with the soil in the plain below. 
What are called the natural walls of North Caro- 
lina are basaltic dikes, formed of columnar or pris- 
matic masses, fitting close to each other, and lying 
with their lengths across the wall, and showing 
their ends on its sides as in the following sketch. 
Basaltic Dike. 
A trap formation, about three miles in breadth, 
extends along the Bay of Fundy, in Nova Scotia, 
a distance of 130 miles. It rises into stupendous 
precipices, and exhibits basaltic and greenstone col- 
umns 300 or 400 feet high, against which the waves 
and tides beat. This range affords a very great 
abundance of beautiful minerals, such as amethyst, 
rock crystal, chalcedony, agate, specular iron ore, 
