240 E. T. Long — Minor Faulting 



a few degrees NW-SE of a true E-W line is, therefore, in 

 keeping with the other surprising fact of the direction 

 whence came the pressure developing the faults of the 

 Encrinal layer, and in reality is what should be looked for, 

 if truly related to the Appalachian Chain. 



A dike ivhich gives some collateral evidence. 



A feature which, on first sight, might in some respects 

 seem at variance with the previously expressed facts, is 

 the presence of a peridotite dike on the crest of the major 

 anticline. It was exposed five or six years ago in the east- 

 ern end of the quarry operated by the Portland Cement 

 Company at the point given its name. Rising from the 



Fig. 7. — Inclusions of Tully limestone in a weathered peridotite (ser- 

 pentine) dike at Portland Point. Notice the fine bedding planes of the 

 limestone. 



Hamilton, which forms the floor of the quarry and cutting 

 entirely through the Tully limestone it intrudes several 

 feet into the Genesee shale above. For the region it is 

 quite sizable, varying from 12" to 18". The strike of the 

 dike, N 3°-6° W, is not in conformity with the postulated 

 direction of movement, which however is to be accounted 

 for by the fact that the dike is obviously here following the 

 course of one of the numerous joints belonging to the 

 N-S system. Its contact with the country rock is often 

 very close, there being no evidence of filling, but on the 

 other hand there are many places where the contact is 

 ragged, streamers of the magma having entered the lime- 

 stone and in some cases pieces of the Tully being broken 

 off and incorporated in the peridotite. (See fig. 7.) Con- 



