18 GEOLOGICAL SURVEY OF THE TERRITORIES. 



approach the mountains, we pass over many beds of quartz, black gneiss, 

 seams of feldspar, with now and then a bed of massive feldspathic 

 granite. These rocks are nearly vertical in position, and in most cases 

 project above the superficial drift so as to be barely visible, with a 

 strike nearly north and south. The intercalated beds of massive un- 

 stratified feldspathic granites are thin at first, while the gneissic beds 

 are the most prominent ; but as we approach the base of the mountains 

 the red feldspathic granites rise in thick picturesque ridges, fifty to one 

 hundred feet high, like ruined walls, lending a peculiar as well as pictur- 

 esque appearance to the landscape. These granites afford most excel- 

 lent rock studies of their kind. The tendency to weather into rounded 

 forms by exfoliation and the jointing are shown very finely. The 

 principal lines of fracture are most continuous, and have a strike east 

 and west, and southeast and northwest, while the other set trend nearly 

 north and south, or northeast and southwest. The tendency to exfolia- 

 tion by the stripping off of thin concentric layers has enlarged the 

 openings sometimes several feet. The granites are thus divided into 

 rather regular rhomboidal masses, many of which have fallen down at 

 the foot of the ridges, and by exfoliation have been so rounded that they 

 appear like immense transported boulders. The texture of the rock is 

 really an aggregate of large crystals of reddish feldspar, with quartz 

 and mica ; the feldspar so predominating that it gives the character to 

 the rock. The mica usually occurs in small masses and in limited quan- 

 tities. The gneissic rocks are divided by the jointing into more regular 

 cuboidal blocks, and have suffered comparatively little from exfoliation. 

 The gneissic strata diminish while the massive granites increase as we 

 approach the main range, which is composed almost entirely of the 

 latter. The examples of anticlinals and synclinals in the metamorphic 

 rocks are nowhere better shown than around Laramie Peak. It would 

 require a detailed geographical as well as geological survey, with maps 

 and sections constructed on a large scale, to show the various axes of 

 upheaval. 



The valley of the Cottonwood Creek, which extends along the east 

 base of Laramie Peak and rises about five miles south of it in the main 

 crest, is a beautiful synclinal. A series of short parallel ridges rise to 

 the very summit of Laramie Peak, on the east side, inclining eastward, 

 while on the opposite side is a similar series of ridges, although much 

 lower, dipping to the westward. These anticlinal and synclinal open- 

 ings give passage to the little streams and ravines or form the open 

 grassy plains which are so pleasant to the Indian. Sometimes these 

 valleys expand out into beautiful oval, park-like areas, which at the pres- 

 ent time are the favorite resorts of the wild game, and, if the country 

 were ever settled, would attract a pastoral people. Emigrants from the 

 mountainous districts of the Old World would find here a scenery not un- 

 like that of their own country, with pure air and water- and a mild and 

 extremely healthy climate. Cereals and roots of all kinds could be raised 

 sufficient to supply the wants of such people, while the raising of stock 

 would be a source of wealth both to them and to the country. It is 

 somewhat strange that the Laramie range should give origin to no im- 

 portant stream. Both the Platte and the Laramie Rivers flow directly 

 through it. While the springs or little streams are not uncommon, this 

 range cannot be regarded as well watered, and in the autumn the water 

 supply is somewhat limited. This may be accounted for from the fact 

 that the snows of winter are very light and the amount of rain falling 

 during the year quite moderate. Laramie Peak, which is the highest 

 point north of Long's Peak, is not more than ten thousand feet high, 



