18G9.] 4^ [Haydcn. 



boulders, some of them 3 to 4 feet in diameter. The Weber river through- 

 out the greater part of its course seems to plougli through a monoclinal 

 valley; but just before reaching the entrance of Lost creek it seems to 

 pass along a local synclinal valley. A long ridge of conglomerate extends 

 down from the direction of the Wasatch mountains, nearly north-east and 

 south-west, inclining nearly north-east 5° to 10°. At this point, the 

 Weber, instead of continuing in the synclinal valley, cuts through the 

 ridge, isolating a portion about half a mile in length and forming a huge 

 chasm, or gorge, which is called here the Devil's Gate. After passing 

 through this ridge, the Weber receives Lost creek, and makes an abrupt 

 bend to the southward ; and here are exposed an immense thickness of 

 the older rocks in a nearly vertical position. These rocks extend down 

 the Weber river four miles or more, when the beds abruptly change from 

 the nearly vertical position to a nearly horizontal one . 



Commencing near the "Narrows," or the mouth of Lost creek, we 

 have a considerable thickness of the Jurassic limestones and marls, dip- 

 ping 70° or 80° north-east, of a bluish ash color, very hard and brittle, 

 cleaving into thin layers, and fracturing in every direction, so that the 

 sides of the hills are covered to a great depth with its debris. Then comes 

 a series of mud shales, with ripple marks, some layers of very white sand- 

 stone, and a thick bed of hard red sandstone, destined to take the highest 

 rank among the building stone of Utah. It can be easily wrought into 

 fine forms for culverts, fronts for buildings, caps and sills, &c. Then 

 comes a vast thickness of gray, and dark gray, more or less cherty, 

 limestones, which are probably carboniferous ; and below these again a 

 very hard silicious rock, oftentimes massive, which I referred to the 

 Potsdam period, portions of Avliich are filled with holes at right angles to 

 the layers, very similar to much of the Potsdam east of the Mississippi 

 pierced by Scolithus linearis. In this quartzose group there is a bed of 

 shaly limestone, 6 to 10 feet thick. A few indistinct molluscs, were ob- 

 served in the limestones and the mud shales. 



The distance from the mouth of Lost creek to the end of the nearly 

 vertical series of rocks is about three miles. So that we have here a 

 thickness of strata not much less than two miles from the top of the 

 Jurassic downwards so as probably to include the Silurian. 



At the mouth of Lost creek, there is a remarkable example of non-con- 

 formity in hills of different ages. The reddish conglomerate rests directly 

 upon the upturned edges of the vertical beds described above, and it is an 

 important question what has become of all the intermediate beds, contain- 

 ing the coal, which are so conspicuous about 5 miles above Echo city. 



Descending the Weber from the " Narrows " we find some of the most 

 remarkable rugged scenerj^ in the west. The walls are very noticeable, 

 and are formed of two beds of limestone, projecting from the sides of the 

 valley, at right angles, from between which 10 or 12 feet of loose material 

 has been washed out. Near the tunnels the rocks on the left side of the 

 A^ieber dip about 10°, nearly north, while on the other side the strata 

 incline in the opposite direction 3° to 5°, as if the valley was anticlinal. 

 A. P. S. — VOL. XI — G 



