[ 174 J 84 
The route ‘ious the North fork of the Platte afforded some of the best plants in the collection. 
The senecio rapifolia, Nutt., samba in sesee pee. quite to the Pet Aca a —— 
ifolia Torr. in James’s plants, Dr. J 
_ vifolius, Nutt. ; eriegonum parse Sa and cespitosum, Nutt.; shepherd argentea, ‘Natt, 
and geranium Fremontti, a new species, (near the Red Buttes, ) were found in this part of the 
_joumey. In saline soils, on the Upper . Platte, near the mouth of the Sweet Water, were collected 
"several Sage RR one of which was first discovered by Dr. James, in Long’s 
m ; and although it was considered as a new genus, I did not describe it, owing to the want 
of <i ripe fruit. It is “ plant doubtfully referred by Hooker, in his Flora Boreali Americana, 
to Batis. He had seen the male flowers only. As it is certainly a new genus, I have dedicated it 
~to the excellent commander of the pepe; as a well-merited compliment for the’ sian 
rendered North American botany. 
The Sweet Water valley is a sandy ‘plat, about one hundred and twenty miles ion ae ‘een 
sual about five miles broad; bounded by ranges of granitic mountains, between which the valley 
formation consists, near the Devil’s gate, of a grayish micaceous sandstone, with nee and white 
_— At the encampment of August 5th-6th, there occurred a fine white argillaceous sandstone, 
coarse sandstone or pudding-stone, and a white calcareous sandstone. A few miles to the west 
- that position, Lieutenant Frémont reached a point where the sandstone rested immediately upon 
the granite, which, thenceforward, along his line of route, alternated with a compact mica atin 
Along the Sweet Water, many interesting plants were collected, as may be seen by an ex 
‘tion of the catalogue ; [ would, however, mention the curious enothera Nuttullii, Torr. and Gr. 5 
eurotia ieviatie: e- ; (Diotis lanata, Pursh:,) which seems to be distinct from EZ. ceratoides ; 
ther mop G Natt; + gitia: pulchella, » Deals senatio apartoides, Tor. and Gr. a new 
Spasien,-ened-Sour efivniip Tran » Dougl., &e.) Near the mouth 
ohthe:Raecest Welet: ene Steal the landuge sriapilors, Tort, @ species firet described in my Dr. 
James’s Rocky Mountain Plants. On the upper part, and near the dividing ridge, were collected 
‘several species. of castilleja ; penistemon micrantha, Nutt, ; several gentians ; the pretty little 
androsace occidentalis, Nutt. ; solidago ineana, Torr. and Gr. | ; and two species of ise ectig 
one of which was new. 
On the 8th of August, the exploring party crossed the. a snbedignibibes hail 
of the plains at the foot of the diountsins, on the western side, to be sandy. From Laramie’s fork 
to this point, different species of artemisia were the prevailing and characteristic plants ; occupying 
‘the place of the grasses, and filling the air with the odor of camphor and turpentine. Along Little 
Sandy, a tributary of the Colorade of the West, were collected a new species of phaca (Ps scot 
tates and parnassia jimbriata. 
On popepicsuionsig aga itieet Rages they entered the defiles of the Wind river eitiliaiiay a 
ck , and i 
= wie Dante meni onan pect ac sscrorage 9 
