1902.] HATCHER — OLIGOCENE AND MIOCENE DEPOSITS. 127 



aspect was that of the remains of a dead and decayed forest on the 

 margin of some stream, where only the less destructible knots and 

 stumps would endure sufficiently long to be finally covered up and 

 preserved. In this same region there were discernible certain 

 strata which seemed to indicate that during the deposition of these 

 beds there had been at several horizons an accumulation of vegeta- 

 ble mould or humus, and on Dry Creek, some five miles northeast 

 of Chadron, in Dawes County, Nebraska, I observed near the base 

 of the Oreodon beds a stratum of some two feet of dark-colored 

 humus, clearly indicating that this region had not been occupied 

 by a great lake while this stratum was being deposited. 



The advocates of the lake theory have always maintained that 

 the fine clays of the Oreodon and Titanotherium beds were 

 deposited in the deep and quiet waters of the lake, explaining the 

 absence of the remains of an aquatic fauna, such as a lake of so 

 great dimensions might in all reason be expected to maintain, on 

 the theory that this lake was of such a saline or alkaline nature as 

 to render its waters uninhabitable by crocodiles, turtles and fresh- 

 water fishes. But I have shown that the remains of such animals 

 do occur, though sparsely, wherever there is evidence of sufficient 

 water to maintain them. The character and abundance of the 

 mollusca and aquatic plants found in the thin limestone lenses 

 throughout the clays show that such bodies of water as were pres- 

 ent, although limited in area, were eminently well adapted to fresh- 

 water life. The great abundance of land-tortoises in the clays and 

 their almost complete absence in the sandstones is very strong if 

 not positive evidence that the former were not deposited in the 

 bottom of a great lake, for I do not believe that any one will 

 assume to explain the present distribution of the remains of these 

 land-turtles on the lake theory. After a careful consideration of 

 the materials composing the White River deposits and the distribu- 

 tion and character of the fossils throughout the sandstones, con- 

 glomerates, clays and limestones, the present writer believes that 

 the sandstones, conglomerates and a portion of the clays were 

 deposited in river channels, while the limestone lenses, so rich in 

 the remains of aquatic plants and mollusks, originated in shallow 

 ponds and lakes scattered over the higher table-lands and the broad 

 flood-plains of the rivers, where for the most part the finer clays 

 were deposited by occasional inundations and through the agency 

 of the winds. Such a theory as to the origin of the White River 



