41 



disappear under a surface of drift and rich alluvial deposit, and are 

 seen no more until we reach the Gros Ventre Valley. The nucleus of the 

 divide is composed of a dark cellular trachyte, over which we rode for 

 half a mile through the timber. This is the first igneous rock thus far 

 noticed in the Wind Eiver Mountains, which are, in this respect, in 

 striking contrast with the rugged mass of volcanic ranges that extend 

 for a hundred miles to the northward. A loose, friable, gray sandstone r 

 met with in places on the surface, is suggestive of Tertiary beds, which 

 appear in great thickness at the first break on the tributaries of the 

 Gros Ventre, and probably cover the slopes on both sides nearly up to 

 the top of the dividing ridge. Specimens of mica in line large plates are 

 found at Union Peak, a short distance south of this point. 



The flora of this region offers a far greater variety and attractiveness 



than in the Wind Eiver Valley, and here becomes the chief feature of 



interest. Starting out from our camp at the foot of the divide we pas- 

 at once into green meadows and up the slopes through thick shrubbery 

 and forests of spruce and pine, where the dull monotony of the plains, 

 with their sage brush and bad-lands, is soon forgotten in the cool, re- 

 freshing mountain air, among beautiful flowers and crystal streams. 

 The shady woods are everywhere carpeted with Herberts agni/olium f 

 Arctostaphylos Uva-urm^ Linnwa borealis, and various mosses, but the 

 ferns are conspicuous for their absence. In all this Rocky Mountain 

 region they are among the rarest of plants. Bat a single species was 

 collected on our trip, found at the Yellowstone Falls. There is no lack 

 of dark, moist places and crevices of rocks, but they are seldom found 

 even where the conditions seem most favorable for them. The surface 

 is rich with the accumulated vegetable debris of centuries, and abun- 

 dantly supplied with water from melting snows. The extreme variation 

 between deep shady canons, swampy meadows, and dry hill-sides offers 

 a wide scope for variety of plant forms, but notwithstanding this the 

 number of species is comparatively few and far less than appearance at 

 first sight would indicate. Ascending to the higher plateaus we find 

 little parks opening out in the timber where a characteristic subalpine 

 flora is displayed in full force. Different species of Towmendia, Eri- 

 I/iron, HeUenium Hoopsii, Polemonium cwruleum, Viola canina, a new 



dwarf variety of Veronica Americana, Pedicularis Grwnlandica, and P. 



pr ocera, Eriogonum umbellatum, Calochortns Nuttallii and Zygadenm 

 elegans. Among the more showy and attractive kinds a beautiful 

 columbine, with white, buff, and sometimes pale blur flowers {Aguilegia 

 ewrulea), regarded as one of the finest Rocky Mountain plants and 

 already largely cultivated, was conspicuous in partially shaded places 

 at 9,000 fret and upwards. Several species of Delphinium, witU par- 

 ticularly deep blue flowers, two or three scarlet Castilhias, Lupinw argen- 

 tem 3 Pentstamon glaber, and P. strietus, Mimulns Lewisii, Merteima 



Siberica, a variety of Phlox lonf/ifolia, pure white and lying iu thick 

 masses over the ground, and many others with pretty faces and hard 



