130 BULLETIN OF THE ESSEX INSTITUTE. 



southern contact with the granite is exposed and hades 

 steeply to the southwest ; and some small branches pene- 

 trate the granite. The dike trends about E. S. E. and 

 re-appears in force on the east side of the valley, at the 

 base of a dark cliff of granite (17). This dike has here 

 a maximum width, though possibly enclosing some 

 granite, of about four hundred feet. On the crest of the 

 spur it is narrowed down to about two hundred feet ; and 

 six hundred feet of granite separate it from the fault,, 

 beyond the abrupt eastern termination of the fault dike. 

 All the indications favor a strong southwest hade ; and on 

 the east slope of this spur it is seen very clearly that the 

 fault hades southwest at a very flat angle (45° or more). 

 The granite passes obliquely up over the edges of the 

 Fountain beds, which for a breadth of several hundred 

 feet are overturned about 10°. 



On the first branch of the next main spur, we cross, 

 from the fault southward, nearly eight hundred feet of 

 granite, and then, high up on the united spur, come to 

 about one hundred feet of sandstone. A few yards 

 farther east, on the second branch of the spur, this sand- 

 stone seems to broaden out to four or five hundred feet. 

 The next spur (18) is a short one which the fault cuts 

 low down on its end slope ; and, immediately south of 

 the fault and the outcrops of the Fountain beds, are four 

 hundred, and possibly five or six hundred, feet of sand- 

 stone. The south Avail is cut by a prospecting tunnel ; 

 and it can be clearly seen, both in the tunnel and in the 

 ledge above it, that four feet of granite separate the main 

 body of sandstone from a parallel two-feet dike of sand- 

 stone. The hade is S. W. about 45°. This tunnel spur 

 is directly at the head of the little or western Ked Rock 

 valley. All the way down the west side of the valley 

 the Fountain beds dip E. S. E. about 30°; while on 



