302 Messrs. Jackson and Alger on the 
gles, if it continues to any extent. But we were unable to dis- 
cover the precise spot where the ore is crossed by it; a discovery, 
which, considering the nature of this dyke, might have disclosed 
some important facts. This spot, however, must be met with ere 
long by the miners, in the progress of opening the bed, as it is 
found most advantageous to remove the ore to the depth of but 
a few feet from the surface. 
In the vicinity of this dyke, we observed several irregularly 
shaped masses of metalloidal diallage, which, when struck with 
the hammer, were sonorous, ringing with a sound not unlike 
that produced on striking a solid mass of metal. It is of a 
grey color, has an interwoven, laminated texture, and breaks 
with great difficulty into rough, splintery fragments, which re- 
flect from the surfaces of their lamine the metallic lustre peculiar 
to this sub-species. We also noticed several scattered masses 
of that variety of amygdaloid called toadstone, possessing the 
characteristic appearance of this rock from Derbyshire, and 
resembling that found at Brighton in Massachusetts by Godon, 
an accomplished French naturalist.* 
From whence came these boulders and those of common trap 
that are now extensively spread over the southern parts of this 
Province, so distant from any rock to which they bear the least 
resemblance? We may venture to infer, without being charge- 
able with a disposition to support a mere visionary hypothesis, (for 
we believe it founded on data which must carry conviction 
to most minds,) that those of common trap and vesicular amyg- 
daloid were derived from the trap-rock ledges of the North 
mountains, and transported hither by that great and sudden 
* See his paper on the structure of Boston and vicinity, in Vol. III. of the 
Academy’s Memoirs, page 127. 
