GEOLOGICAL SURVEY OF THE TERRITORIES. 151 



either east or west of the limestone range. The evidence is plain 

 enough, however, that the basalt did originally form a thick covering 

 in this valley. 



Near the bend of Bear River are several points of effusion, and three 

 or four ruins of old craters can be seen. On the east side of the lime- 

 stone ridges, in the valleys of the sources of the Blackfoot Fork, there 

 are a number of real craters, the rims of which are composed of lava of 

 quite modern appearance. One of these craters, not more than ten 

 miles north of the Soda Springs, is very distinct, about one hundred and 

 fifty yards in diameter, from one edge of the rim to the other, nearly 

 circular; the west side of the rim is about 50 feet above the grass-cov- 

 ered, inner space, which is eighty yards in diameter. All the rocks are 

 extremely porous, and have the appearance of comparatively recent 

 action. Indeed, but few, if any, important changes have taken place in 

 the surface since the eruption of these basalts, and therefore it must 

 have occurred either during or immediately prior to our present period. 



In general terms, we may describe this portion of the country as com- 

 posed of nearly parallel ranges of mountains or mountain hills, seldom 

 rising more than 1,500 feet above the intervening valleys, but with here 

 and there a higher peak 2,000 to 2,500 feet. On the east side and ex- 

 tending off to the drainage of Green Eiver, these ranges are mostly 

 composed of limestones or quartzites, which are undoubtedly of Carbon- 

 iferous age. They trend nearly north and south, and, though sometimes 

 broken up at points, preserve a remarkable degree of uniformity. They 

 are folds or wrinkles in the crust, from the surface of which nearly or 

 quite all the older sedimentary rocks have been removed by erosion, 

 leaving the Carboniferous group in pretty nearly its full force. On the 

 west side, however, about the lower caiion of the Port Neuf, the lime- 

 stones have been stripped away, and an immense thickness of meta- 

 morphic strata of uncertain age is exposed. In the intervening valleys, 

 are the Lake deposits, as usual, and at a modern date, the evidence of 

 the eruption of the basalt. About the sources of this Blackfoot Fork, 

 the influences of the basaltic outflows are very marked. Along the sides 

 of the ranges of hills or mountains are deep ravines, extending up to 

 the crest or water-divide. Thej^ are seldom cahons or gorges, though 

 the walls are in some instances rather abrupt. These ravines gather 

 the drainage from the hills, and in the valleys numerous springs break 

 forth, the Vv-^aters of which contain great quantities of lime in solution. 

 Large deposits of this lime are met with long before reaching Soda 

 Springs at the bend of Bear Eiver. Indeed, this group of springs, which 

 is usually very remarkable, is but the center of a great district ex- 

 tending in every direction, only the ruins of which remain at the pres- 

 ent time. Some of these ruins bear traces, at this time, of a good deal 

 of former beauty. In one locality quite a large area was covered with 

 the semicircular basins, with scalloped rims. 



But one of the most remarkable features of this region is the bend of 

 Bear Eiver. By examining the map it will be seen that the river, after 

 flowing nearly northward from the Uintah Mountains about two hundred 

 and fifty miles, makes an abrupt bend, and returns, flowing southward 

 about the same distance into Great Salt Lake, not more than lilty miles 

 from its source. There is really only one important range of mountain^ 

 or hills between the two portions of the river. I was unable to obtain 

 from the i)resent surface features of the country, a satisfactory I'eason for 

 the singular conduc^t of this I'iver. The wide ])arallel valley which comes 

 up over the lake, known on the maps as Cache Valley, opens directly into 

 the Upper i'ort Neuf, and continues nearly to Fort Hall, while Bear Eiver 



