212 GEOLOGICAL SURVEY OF THE TERRITORIES. 



westerly direction from station 48, granite is crossed, and a short dis- 

 tance beyond the same stratum is found, bearing the same relations to 

 over and under lying formations. It is evident, from the stratigraphical 

 character of the grauite, and from the position it occupies with refer- 

 ence to the sedimentary beds, that at the place to which these remarks 

 apply, it was formed from sedimentary deposits tliat have now disap- 

 peared. Above the quartzite is a thin stratum of yellow siliceous 

 shales, containiug narrow interstrata of softer shales. In these the well-, 

 known and characteristic pseudomorphs after salt were found. During 

 the formation of the Devonian beach that now remains quartzite and 

 quartzitic shales, portions of the water, that even at so early a geological 

 period contained sodium -chloride, were separated from the main body. 

 Upon evaporation the.mineral constituents of the water crystallized. Sub- 

 sequent inundations of the places that had scarcely been laid dry, brought 

 with them sand and silt, covering the newly-formed crystals. By the 

 gradual percolation of water through the cover the salt was dissolved, 

 and a quantity of the material composing the cover found its way into 

 the cavities thus produced. It will be noticed, therefore, that whenever 

 these pseudomorphs of sand after salt are found in positu, the crystals 

 will be observed on the lotcer side of strat um containing them. Occurrences 

 of this kind are not uufrequent in younger formations both of this 

 country and Europe. Besides these pseudomori)hs, scales and frag- 

 ments of bones are found, belonging to some fish of considerable size. 

 Too little material could be collected to admit of any identification, 

 even only generically. Small scutellss also occur, probably belonging 

 to the same animal. This stratum, as well as the quartzite underlying 

 it, can be traced on the southern side of the granite strip. 



Above this the limestones set in. On station 48 it presented a very 

 curious appearance. In every direction the isolated stratum is traversed 

 by vertical fissures, sometimes 8 to 10 feet in width, sometimes only a 

 few inches. Throughout the entire mass innumerable small cracks occur, 

 so thoroughly breaking up the limestones that it was a difficult matter to 

 obtain even small tossiis that were not already broken. The whole 

 phenomenon was that of the result of a vertical force acting with lim- 

 ited lateral pressure. I ascribe it to the same cause that produced the 

 metamorphosis of the underlying strata. As in the two preceding cases, 

 this limestone also continues farther south, forming an abrupt bluff 

 toward the northeast and east. The continuation shows more strata 

 than were observed on station 48, but the horizon for fossils remains the 

 same. Here the evidence of decomposing and disturbing influences is not 

 so thoroughly marked, although it can readily be noticed. Thousands 

 of fossils were found on station 48 belonging to a few species only, but 

 nearly all of them in a very poor state of preservation, owing to the 

 causes above given. At some places the limestone was almost entirely 

 composed of the remains of BracJiiopods, while at others they were 

 distributed more sparingly. This stratum seems to me to mark the 

 upper limit of the Devonian formation in that section of country, and, 

 although no very decisive paleontological evidence can be adduced for 

 assigning the overlying beds to the Carboniferous, it must be remem- 

 bered how very closely the organic remains of the Upper Devonian and 

 Lower Carboniferous are related to each other in our western groups 

 belonging to those formations. A number of species were found in the 

 limestone of station 48 and its continuation southward, which Professor 

 F. B. Meek has kindly identified. He describes, from the material sub- 

 mitted to him, a new species,* the description of which is given below. 



* Bulletin United States Geological and Geographical Survey, second series, No. 1, 1875, 

 page 4G. 



