209 



trap, is coarsely crystalliiK', and there is not the slio-litest indica- 

 tion that it is eruptive throu<>]i the sedimentary rocks. No veins 

 or apophyses of granite penetrate the slate, and the normal coarse 

 texture of tlie p^ranite is unchanged near the contact. But the 

 ahi-upt way in which the diabase ends against the conglomerate 

 and the obvious partial dislocation or lateral shifting of the 

 slate ai'e certainly very suggestive of faulting. Again, the 

 slate, although its strike is parallel with the granite, clearly 

 dips against the latter ; and in all the outcrops it shows great 

 disturbance, being strongly contorted and faulted, or, locally, 

 completely crushed. Tiie contact between the granite and slate 

 is probably a strike-fault with the downthrow to the north ; and 

 all the sedimentary beds are probably cut by a transverse fault 

 along the west side of the granite, which, as the arrows on the 

 map indicate, downthrows to the west south of the granite-slate 

 contact and to the east north of it. Along its contact with the 

 slate the granite continues scarcely 200 feet, ending as abruptly 

 as it bejTan. In the direct line of the g^ranite we here find 

 broad outcrops of the slate, which, with a southerly dij> of 

 80°, is exposed almost continuously for its normal breadth ; 

 while the dike of diabase, as before, abuts squarely against the 

 conglomerate. Evidently, the granite and trap are bounded 

 on the east as well as on the west by a fault ; and these two 

 faults are obviously reversed in throw or compensating. To 

 avoid their indefinite extension, they are represented as con- 

 verging northward ; but that is not strictly required by the 

 observed facts. The main point, however, is that the facts 

 appear to justify us in regarding the granite and its included 

 diabase as a somewhat rectangular block which has been ele- 

 vated relatively to the bordering strata, the uplift having been 

 sufficient to carry the sediments normally overlying this mass 

 of granite above the present plane of erosion. Southward this 

 block of granite is continuous with tiie main area ; and it is 

 simply a displaced portion of the general granitic floor upon 

 which the sediments rest. The evidence for the second fault is 

 occAs.rArERS 15. s. X. n. IV. 14. 



