a 
aie [ 174] 
containing the fossil ferns also effloresce a salt, which is apparently ve 
ium. This fact seems to indicate the presence of fossil salt 
this distance north of the known locality, and is a circumstance. which vs 
naturally Se ma as part of the evidence of identity in the age of the 
formations 
This region is unquestionably one of the highest interest, both as regards 
its economical resources, and equally so in the contributions which it will 
yield to geological science. In the specimens from the vegetable locality, 
Ihave been able to indicate seven or eight species of fossil ferns, most o 
which are new. Further researches will doubtless greatly multiply this 
number. Besides these, as hew species probably peculiar to our continent, 
they have a higher interest, inasmuch as they show to us the wide extent 
and the nature of the vegetation of this settee coal period. In the broad 
fields of the west, we shall have an opportunity of tracing it over large and 
unbroken areas, and many highly intetestihig results may follow its com- 
parison with the vegetation of the true carboniferous period. 
Again: since these deposites have evidently been guide over large tracts 
of country, it is not unreasonable to suppose that the quantity of material 
accumulated will be very great, and that we may expect to find profitable 
coal beds in the rocks of this age. This subject, besides being of high 
interest to science; is of Some prospective economical importance, though 
perhaps too segs? to dwell upon, while the country remains so little ex- 
plored as at pre 
Longitude 112°, ‘latitude 42°.—The specimen No, 72 is a grayish-blue 
limestone, efflorescing a salt upon the surface, “from the Hot Salt Springs 
of September 13, 1843.” No. 108 is a siliceous limestone of a brownish- 
gray color; where exposed, the surface becomes porous, from the solution 
and removal of the lime, while the siliceous particles remain. From the 
general lithological characters of the specimen, it is probably a modern 
rock, but its precise age cannot be decided. 
Longitude 112°, latitude 413°.—The single specimen from this losality 
is, eet present state, ‘ ‘granula r quartz.” Si Tt is, Newerers very evidently, 
preserved. This rock proba ably comes out frosti pr the siliceous lime- 
stone last described, both having been -altered by modern igneous action. 
The character of the specimens from the next locality—three-quarters of 
a degree, farther west—may perhaps throw some light upon the present 
Gotdition of those last name 
Longitude 1122°, latitude 429°; at the American Falls of Snake river.— 
The collection from this point presents the following, in a descending order. 
These specimens are numbered 94, 96, 97, 101, 102, 106, and 107: 
1. A botryoidal or ‘coneretionary lava, No. 94. 
2. Obsidian, No. 1 
3. Vitrified Ey eat No. 1 
4, A whitish ash-colored chalk. or pie le No. 107. 
e: A light ashy volcanic sand, No. 
6. Brown sand, volcanic. (?) 
These are all apparently volcanic products, with, probably, the excep- 
tion of Nos. 106 and 107, which may be sedimentary products ; presel 
altered by heat. The two lower abodes are evidently volcani¢ sanc ‘oF. 
“ashes;” the upper of these, or No. 5, has all the characters. of, pulverized. 
pumice stone, and is doubtless of similar origin. | 
