124 GEOLOGICAL SURVEY OF THE TERRITORIES. 



comparatively few exposures of the basis rocks, on account of the super- 

 ficial drift which covers all this country. Still we find along the banks of 

 the river, near the stage station, the same black plastic cretaceous clays 

 with Ostrea congesta and a few remains of fishes; also the chalky marls; 

 and about two miles above, the long high ridges, on either side, extend- 

 ing up for several miles, composed of the rusty yellow sands and sand- 

 stone of the lower cretaceous. The dip of these beds is very gentle, 

 hardly perceptible to the eye. 



The Big Laramie is a very clear stream, about fifty yards in width and 

 averaging about two feet in depth, easily forded in most places. Like 

 most of the western streams, the difference between high and low- water 

 mark is very great. In spring and early summer, when the snows of the 

 mountains melt, these streams become formidable rivers. The soil along 

 the bottoms appears to be very good ; the grass grows quite heavily, and. 

 hundreds of tons of hay are cut here by the settlers for winter use. The 

 grazing is excellent, and numerous ranches have been started all through 

 the valley for the purpose of raising stock. Even at this season of the 

 year a great variety of flowers covers the surface. The Composite and 

 Leguminosw prevail in numbers, and yellow is the dominant color. As 

 we approached the foot-hills of the mountains the transition beds appeared 

 on the ridge, rocks of more recent date having been swept away by erosion. 

 Fragments of pudding stone and rusty-colored masses of sandstone were 

 scattered here and there ; then beneath them were exposed about four 

 hundred feet of variegated arenaceous layers of uncertain age, perhaps 

 Jurassic ; then a little higher up the side of the mountains were revealed 

 the red beds, fifteen hundred feet or more in thickness, presenting won- 

 derfully picturesque scenery. All these beds seem to have been lifted up 

 in a nearly horizontal position, so that they present lofty escarpments, 

 sometimes cone-like or pyramidal in shape, revealing each layer in the 

 order of succession. The harder layers yielding less readily to atmo- 

 spheric influences, project out from the sides, adding much to the nov- 

 elty of the view. Most of the beds incline from the flanks of the moun- 

 tains at various angles, 3°, 8°, 15°, and then continue along the river, 

 winding for twenty-five miles among the mountains almost to the foot 

 of the snow-covered peaks. 



On either side can be seen a number of syenitic nuclei, but I did not 

 find the unchanged rocks so clearly in contact with them that I could 

 define their relation to each other. 



Before reaching the mountains we passed a series of alkaline lakes, 

 which are simply shallow depressions, receiving the drainage of a small 

 area without any outlet. From these shallow lakes the water is evapo- 

 rated, so that in the autumn the bottoms are dry and covered with a white 

 incrustation which looks much like water in the distance. One of these 

 lakes still contained water and seems to have a fair supply at all seasons. 

 It is almost a mile in length and half a mile in width. In the spring 

 these lakes are quite large and are filled by the overflow of the branches 

 of the Big Laramie, which are greatly swollen by the melting snows. 

 Great quantities of fish are swept into these lakes from the neighbor- 

 ing streams, and in the autumn the water becomes so alkaline by evap- 

 oration that the fish die in great numbers along the shore. It is a 

 curious fact that not a single trout has ever been taken in any of the 

 branches of the North Platte, unless a few have been caught in the 

 Sweetwater, while the branches of the South Platte are filled with 

 them. 



After entering the foot hills of the mountains, the Big Laramie and 

 its branches wind their way through the narrow valleys or gorges 



