Geographical Notices. 227 
This, however, is impossible, simply because specimens of nearly 
all the species found at the various localities have been quarried 
from the same bed at Blackbird Hill, and the whole,—not a part 
only—of this formation, passes beneath all the other Cretaceous 
tocks of the northwest. In addition to this, we have extensive 
collections of plants from the Tertiary of Nebraska, not a single 
species of which is identical with those from No. 1. 
When we stated in some of our papers that it was possible we 
_ even now prepared to believe that it may yet be found to repose 
on Jurassic rocks in that Territory, as it does at the Black Hills, 
in Nebraska. 
Art. XXVIIL— Geographical Notices. No. VI. 
SEMENow’s ExpLorations Iv Cenrrat Asia, 1857.—The 
ingonometrical survey of India, the exploring expedition of the 
3 agintweit, and the researches of Russian travellers 
are making valuable contributions to our knowledge of Cen 
a In a recent number of Petermann’s journal a highly im- — 
la paper is presented in respect to the expedition of P. V. 
‘enow, in the neighborhood of the Balkasch lake. The arti- 
cle is based upon original data furnished by the traveller, and 
dated St, Petersburg, June, 1858. : 
We condense and translate such portions of the article as are 
interesting, regretting that we are not able to transfer it 
entire, 
Telatively insignificant height of the hills which hardly in a sin- 
d 
