212 jReviews — Prof. 0. C. Marsh's Dinocerata. 



I. — The Dinocekata, a MoNOGRAPn of an Extinct Order op 

 Gigantic Mammals. By Othniel Charles Marsh, M.A., 

 F.G.S., of Yale College, New Haven, Conn., U.S.A. 4to. pp. 

 i-xviii, and 237 ; with 56 Plates and 200 Woodcuts. Being 

 Yol. X. of the United States Geological Survey of the Territories. 

 Advance copy issued with the permission of the Director. 

 (Washington: 1884.) 



IN the Geological Magazine for 1880, Decade II. Vol. VII. pp. 

 522-526, we had the pleasure to draw attention to the appear- 

 ance of the first volume of this magnificent series of United States 

 Geological Survey Monographs by Professor Marsh, that on the 

 Odontornithes, or Toothed-Birds, of the Cretaceous deposits of the 

 liocky Mountains in North Amei'ica. 



The present volume, which corresponds in style with it, and may 

 be properly called Volume II. of the series, is equally worthy of the 

 attention of paleontologists. It contains a most complete record of 

 a peculiar order of Mammals which have been obtained by the 

 author with vast labour and expense, and with no little personal 

 risk, from the early Tertiary strata of the great central plateau of 

 the Continent. But we will let Professor Marsh speak for himself. 



" Among the many extinct animals discovered in the Tertiary 

 deposits of the Eocky Mountain region, none, perhaps, are more 

 remarkable than the huge mammals of the order Dinocerata. Their 

 remains have hitherto been found in a single Eocene lake-basin in 

 Wyoming, and none are known from any other part of this country, 

 or from the Old World. These gigantic beasts, which nearly equalled 

 the Elephant in size, roamed in great numbers about the borders of 

 the ancient tropical lake in which many of them were entombed. 



" This lake-basin, now drained by the Green River, the main tribu- 

 tary of the Colorado, slowly filled up with sediment, but remained 

 a lake so long that the deposits formed in it, during Eocene time, 

 reached a vertical thickness of more than a mile. The Wasatch 

 Mountains on the West, and the Uinta chain on the South, were the 

 main sources of this sediment, and still protect it ; but the Wind 

 Eiver range to the North, and other mountain elevations, also sent 

 down a vast amount of material into this great fresh-water lake, 

 then more than one hundred miles in extent. 



" At the present time, this ancient lake-basin, now six to eight 

 thousand feet above the sea, shows evidence of a vast erosion, and 

 probably more than one-half of the deposits once left in it have 

 been washed away, mainly through the Colorado Eiver. What 

 remains, forms one of the most picturesque regions in the whole 

 West, veritable mauvaises terres, or ' bad-lands,' where slow denuda- 

 tion has carved out clifis, peaks, and columns of the most fantastic 

 shapes and varied colours. This same action has brought to light the 

 remains of many extinct animals, and the bones of the Dinocerata, from 

 their great size, naturally first attract the attention of the explorer. 



