888 Recent Literature. [November, 
work of the geologist at any one time or season is but a part, 
and commonly a very small part, of a great system that extends 
over vast areas of country. Thus, in explorations in the Rocky 
mountains, the most assiduous labor of the geologist can cover 
thoroughly, in one season, but a small part of the great range, 
and his discussion of results cannot be complete in itself, but 
must depend largely upon work in the adjoining regions. Rarely 
then, does the geologist find his work so admirably circumscribed 
by nature as did those to whom the exploration of the Black Hills 
was committed. * * * Generally and simply the geological 
structure of the Black Hills is as follows: Around a nucleal area 
of metamorphic slates and chists, containing masses of granite, 
the various members of the sedimentary series of rocks, the Pots- 
dam, Carboniferous, Trias or red-beds, Jura, Cretaceous and Ter- 
tiary, lie in rudely concentric belts or zones of varying width, 
dipping on all sides away from the elevatory axis or region of the 
Hills. From the Hills outward the inclination of the beds grad- 
ually diminishes until all evidence of the elevation is lost in the 
usual roiling configuration of the plains. At numerous points, 
also, within the area of the Hills, are centers of volcanic aes 
tion of an age probably coincident with that of the elevation ° 
the mountains themselves.” ; 
The chapters by Mr. Newton, who died of typhoid fever a 
Deadwood, in 1877, were revised and prepared for the press by 
Mr. G. K. Gilbert, while the report is preceded by an appreciative 
biographical sketch prepared by Professor J. S. Newberry. 
he palzontology of the report, accompanied by sixteen 
orate plates of fossils, is by Mr. R. P. Whitfield; an essay 0” Fi 
microscopic petrography of the Black Hills, with two fine colore 
plates, is by John H. Caswell; while Professor Asa Gray offers 
brief enumeration of the plants, and Mr. Horace P. Tuttle eh 
upon the astronomy and barometric hypsometry of the Black Hills. 
A Memoir on THe LoxotopHopon AND UINTATHERIUM, e 
Henry F. Osborn, Sc.D..—This fine memoir opens auspicious y 
the quarto series of Contributions from the E. M. Museum ai 
A Me ScD. 
A Memoir upon Loxolophodon and Uintatherium. By Henry F. Osbon™ Se. Y 
Accompanied by a Stratigraphical Report on the Bridger beds in the Washakie basi. 
py the 
\CH McMaster, C.E. to, pp. 54, IV plates, 11 maps. Published Mf, ‘e 
elab- - 
nal BS 
