124 Mineralogy and Geology of the White Mountains. 
spathic and white, six feet wide, and contains in abundance imbed- 
ded fragments of granite, like that enclosing the vein, and also of 
slate and trap, all finely contrasted in color with the vein, and 
pasted into it like fragments in a breccia. Fig. 6. 
The circumstances existing at the time this vein was filled, 
may have been these. ‘The granite was consolidated, and cov- 
ered by slaty rocks, (since removed, ) and by masses or fragments 
of trap, which were all fissured simultaneously, and the frag- 
ments of all falling into the fissure were entangled in the fused 
rock thrown up; or the granite was covered with the ruins of 
slaty and trap rocks, and when it was fissured the fragments torn 
off were enveloped together with those of slate and trap, and all 
consolidated. Whatever was the state of things here, the dike 
isclearly not one of segregation, but of injection from below; 
and its relative age is certainly more recent than the consolida- 
tion of the granite, and the period when the slaty rocks were 
deposited in this region, or the ejection of trap. 
Detached Masses of Granite. 
te this vicinity there are numerous detached rocks lying on the 
ground, and some of enormous size, which are fractured through 
and through, sometimes in two pieces, sometimes in more, the 
parts with their salient and re-entering angles exactly correspond- 
ing to each other; and thus proving that they were once joined, 
and have been cracked by violence, and not by decomposition or 
disintegration : the void being such a space as, had it been filled, 
would have made a dike. 
A remarkable rock of this kind, some thirty or forty feet across, 
may be seen near the ‘‘Flume,” fractured in this way, and is a 
mere boulder. The question arises, ‘how were these rocks frac- 
tured ?” 
They were once portions of ledges, and of mountains, and per- 
haps were cracked, but not parted, when the masses were de- 
tached from the main body ; and then water percolating through, 
has, year by year, by freezing, pushed the parts farther and far- 
ther asunder. They could not have been cracked and separated 
by earthquakes where they lie, and they are so numerous, there 
must have been a general cause. 
