426 Scientific Intelligence. * 
Tongue rivers, we have no definite information. The traders say the 
same kind of lignite beds seen along the Yellow-Stone, occur along the 
banks of the former as much as one hundred and fifty miles above its 
mouth. 
The foregoing hasty sketch is given more with a view of showing the 
extent of the country occupied by this great Tertiary lignite formation, 
than with any hope of conveying a definite idea of its precise limits. [ 
it should prove to be only a part of the same extensive fresh water lig- 
nite formation observed by Sir John Richardson on the Saskatchawan, of 
which we have little doubt, then it is highly probable the lignite and 
eoa) formations mentioned by Mr. Isbister as flanking the eastern slope of 
the Rocky Mountains, in the form of a continuous belt from the Saskat- 
poch. 
For the most part, these deposits in Nebraska consist of beds of gray, 
yellowish, whitish, and blue sand, sandstone, clay, &c., with alternating 
sent a remarkable uniformity of character, and as may 
following paper, are all, excepting a few land shells, referable to genera 
usually found in fresh and brackish waters. It is an interesting fact that 
Woolwich and Reading series of English geologists, as well as to those 
the great Lignite formations of the southeast of France, would seem 
to point to the lower Eocene as their position. Yet it may be possible 
these resemblances have resulted from the action of precisely similar 
causes at a somewhat later period. 
It is a little remarkable that these formations differ in many respects 
from those of the White River basin lying so near on the south. In the 
first place they generally contain more sand, are usually characterized by 
of lignite, and as yet have furnished no remains of Mammalia; 
* We are under many obligations to Dr. Issac Lea, of Philadelphia, for the 
privilege of com Re cach age 2 meer 
Mectina oF eatin fossil species with analogous forms in his magnificent 
