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 

 ofi" were enveloped together with those of slate and trap, and all 

 consolidated. Whatever was the state of things here, the dike 

 is clearly 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. 



In 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. 



