SCIENTIFIC SURVEY. g25 



some places there seemed to be a tendency to foliation in the tliick- 

 er and more indurated layers. 



In approaching the stream that enters the Cauquomgomocsis 

 lake on the portage from Alleguash lake, we passed over two well- 

 defined terraces, running parallel to the stream so fur as we could 

 see. Entering Cauquomgomocsis, it was evident that the east 

 side would be the most favorable for geologizing, as it is the one 

 next the mountains, and upon which the strata cropped out. Just 

 east of the entrance the first ledge proved to be clay slate contain- 

 ing considerable mica. The dip in this and the next two ledges 

 is 50° north-west. Near one of these ledges is an embossed rock 

 with striae having a direction of north 10° west, which is more 

 nearly north than any we have met with in this region— a change, 

 no doubt, caused by a local deflection in the direction of the tritu- 

 rating force. The most southern ledge on the east side has a dip 

 of 80° north 30° east. 



A little way to the left of the outlet is the last ledge, consisting 

 of an indurated variety of micaceous clay slate, and having a south- 

 east dip of 80°. There is here a very beautiful instance of local 

 contortion, forming what in carpentery is called an 0. G. mould- 

 ing, showing that while in a soft, plastic condition, undergoing 

 metamorphism, it had been subjected to lateral pressure. It is 

 the same in miniature as what has been demonstrated to have taken 

 place in the Housatonic and Alleghany mountains. Tlio same 

 phenomenon is presented in the strata a few rods above Leadbettcr 

 falls on the west branch of the Penobscot, and on a somewhat larger 

 scale than here. 



On the west side of this lake we observed no ledges ; and although 

 we did not examine particularly, yet we presume from the low, 

 flat character of the shore and adjoining land, that the rocks do 

 not come to the surface. In the south end, a short distance from 

 shore, is a solitary trap boulder some thirty feet long by twenty 

 feet wide and ten feet high. Now taking the directions of those 

 striae as an index, there can be no doubt that this boulder has once 

 formed a part of the trap mountains heretofore spoken of, and had 

 been transported three or four miles by some great iceberg or 

 glacier of the pre-historic period, and deposited where it now 

 rests. 



The rocks of Cauquomgomocsis lake differ from those of Alle- 

 guash lake in the obscurity of the stratification ; the layers are 



