Mineralogy and Geology of the White Momitains. 119 



when the granite Avas not in a consolidated state. Above this, 

 we may observe the dike passing in full width ; then sending off 

 branches from the main body, including apparently detached 

 portions of granite, or separated by long narrow and broad lines 

 of granite ; then becoming confluent into a lesser dike, to be 

 again enlarged, and subdivided into tortuous lines, or stand in 

 ciirved plates, covering concave surfaces on the side of the gorge, 

 from which the granite has flaked ofl^, or in shoots terminating 

 abruptly, or in evanescent lines, every where enclosing granite, 

 and the granite in turn enclosing trap. This constantly varying 

 appearance of the dike and granite at different elevations, forces 

 the conclusion that the granite was fissured while a tenacious 

 mass, and is still united by filamentous portions running in every 

 direction, and the granite and trap both reticulated, so that if it 

 were possible in a given spot to remove one layer after another, of 

 only a few inches in thickness, each new face would present a 

 varied aspect according to the size and inclination of the portions 

 intersected. 



This dike was traced as far as circumstances allowed some 

 fifteen hundred feet high, till the ascent became impeded by 

 a perpendicular front six feet high. The dike was visible above 

 this point till a turn in the gorge, and there can be little doubt 

 that it extends to the top of the mountain, and has completely 

 riven it in two. The gorge is from thirty to fifty feet deep, and 

 at top twenty to thirty feet across, excavated in the rock itself; its 

 sides very steep, vertical, and even overhanging in some places. 

 The trap is generally of a dark or blackish gray, fine grained, 

 crystalline, very compact, hard, fires a little with steel, and con- 

 tains no foreign minerals ; another portion is light gray, and com- 

 pact ; and still another, light gray, seeming like a decomposing 

 earthy sandstone, filled with smooth rounded nodules of the size 

 of a small pea and less, very prominent on a weathered surface, 

 occasionally containing white crystalline matter, but usually 

 earthy throughout, and scratch glass readily. This at the time 

 was saturated with water that runs in the gorge, and the speci- 

 mens being disintegrated, readily parted, and required careful 

 handhng till dried, when they became more coherent. The 

 junction of the dark gray trap and granite is most perfect, as if 

 soldered together; and these specimens presenting a beautiful 

 contrast, may be easily obtained, as a fracture seldom occurs at 

 the line of junction more readily than through the mass. 



