110 Mineralogy and Geology of the White Mountains. 



No. 3. Four feet wide ; direction N. W. and S. E. ; inclines 

 N. E. 35*^ ; variable in color ; specimens of a yellowish brown, 

 clouded with red; others of a handsome light gray ; structure 

 compact ; fracture flaky, with shai'p edges ; translucent on the 

 edges ; fires readily with steel ; minute iron pyrites diffused 

 throughout ; effervesces briskly with sulphuric acid, like No. 2. 



No. 4. Direction E. and W. ; terminates abruptly ten feet from 

 the water in a quartz vein, and with a disconnected lateral shoot, 

 and intersects many quartz veins ; curves at and beneath the 

 water, and unites at the distance of five feet with No. 5. 



4a. Between 3 and 4, consists of three nearly distinct portions 

 arranged in a curve ; convex northerly ; the terminations all ab- 

 rupt, except the lower end of the lowest portion. These are, 

 clearly, parts of what was once a continuous dike, and the dislo- 

 cations evince a disruption subsequent to the injection of the 

 trap ; width of 4 and 4a variable, from six to ten inches. 



No. 5. Direction E. and W. and two feet wide ; breaks a few 

 feet from the water and is dislocated northerly by its whole 

 width, so that the south side of the upper portion is in a line with 

 the north side of the lower part ; continues up the inclined bank 

 to the soil above, thirty or forty feet. 



In this and 4, and 4a, we observe the effects of one disloca- 

 ting throw, which has displaced them all in the same direction ; 

 whether the movement was N. or S., can be determined only by 

 a critical examination of the rocks in place. 



No. 5 is exactly like fig. 89, in Lyell's Geology, Am. edition, 

 Vol. ii, p. 237. 



No. 6. Terminates eight feet from the water in a blade ; inter- 

 sects numerous quartz veins ; six inches wide ; nearly perpendicu- 

 lar ; but the rocks dip at an estimated angle of 60° : another re- 

 sult coincident with the contortion of 4 and 5, and probably from 

 the same cause. Nos. 4 and 5, we have seen, are united ; but all 

 from 4 to 6, inclusive, are so similar in mineralogical characters, 

 they may be regarded as ramifications of the same main fissure, 

 ejected from the same focus. 



Characters. — Color, black ; fracture very uneven ; granular ; 

 strike fire with steel ; contain iron pyrites, and a dark green min- 

 eral diffused in small dots, which in vitreous lustre and hardness, 

 very nearly resembles olivine. 



