310 GEOLOGICAL SURVEY OF THE TERRITOEIES. 



fine texture, which are in turn covered by yellowish shales (/) that can 

 be referred to the Oarbouil'erous, as in section A, Plate VIII, preceding. 

 It seems probable that the Lower Silurian blue limestones underlie these 

 quartzites, although they were not found. 



Scarcely a mile east of this part of Badger Creek, a little north of 

 station 58', the Silurian makes a second turn ; this time from west to 

 east toward north to south, again running parallel to the first line of 

 outcropping mentioned above, thus completing the S-shaped figure. 

 Station 58' is located on the quartzitic strata. A few miles south of 

 this station the limestoues appear, and remain either entirely or par- 

 tiallj' esposed during the remainder of the line followed by this forma- 

 tion in section a. The dip is not steep ; never much exceeding 15° to 

 18°, and is a little north of east. Three or four miles south of station 

 58' the band of sedimentary rocks becomes very narrow. A third turn 

 is taken east of station 57' of about 28° to the west, from which point 

 the Silurian runs down to the Arkansas, bordering the east side of the 

 trachorheites. It is exitosed on the Arkansas for a short distance. 

 On the south side of the river this formation appears again, but no 

 direct connection between the two sections can be traced. 



Only about eighteen square miles are covered by the Silurian, because 

 its breadth is very inconsiderable, although the meandering-line run- 

 ning from station 53 to the Arkansas is almost thirty-two miles in length. 

 Orographically, the Silurian is of slight importance in the formation of 

 plateaus of small extent, sloping oft" gently to the north, northeast, and 

 east. Farther north, beyond the limits of our district, this formation 

 is found occurring in much greater bulk, and it seems that southward 

 the conditions for its formation in Silurian ages may not have been at 

 all favorable. Whether any of the strata above the ones just spoken 

 of should be referred to the Devonian, 1 am unable to say. The poorly- 

 preserved relics of paleontological testimony that could be obtained 

 were so few and so unsatisfactory that I can have no decided opinion 

 upon the subject, although 1 am inclined to think the Devonian, if 

 represented, is no formation of great extent, either vertically or hori- 

 zontally. 



The Carboniferous formation of section a shows some very interesting 

 features. In the eastern portion of the section no rocks were observed 

 that could be referred to this age; it was found only in the western, in 

 connection with the Silurian just spoken of. From station 53, a belt of 

 it stretches along a little east of south, from three to four miles wide, 

 bordered on the east by the familiar coarse-grained red granite, on the 

 west by the Silurian. Korth west of station 54 it forms a small synclinal 

 valley, dipping from either border toward the center at an angle of 7"^ 

 to QC". Adapting its course to that of the underlying Silurian, it makes 

 the sharp bend below station 55, and then, running in an easterly direc- 

 tion, gradually pinches out until it becomes very narrow. Owing to 

 the overflows of trachorheites, only small patches of it are exposed on 

 that easterly line, large masses apparently being covered. Eemaining 

 in a conformable position to the underlying rocks, the* Carboniferous 

 follows the second bend north of station 58', and thence continues south- 

 ward in a very narrow strip for about six miles. At that point then 

 the lower limestones are deflected a little to the west; the sandstones, 

 farther north of no great dimensions, are enormously developed ; and the 

 upper limestones make their appearance. Of the latter, a spur branches 

 off to the east and runs through a granitic country for a distance of 

 about seven miles, dipping northeast to east, and then comes to an end 

 without connecting again. 



