126 HATCHER — OLIGOCENE AND MIOCENE DEPOSITS, [AprU 3, 



with reference to this, for whether the deposits as a whole were of 

 lacustrine origin or not, there could be little doubt as to the 

 aqueous origin of the sandstones. Though for the most part 

 remarkably barren of aquatic life, remains of Trionyx, fishes and 

 crocodiles were found, and in one locality the casts of unios were 

 observed in great numbers. A search in the clays of the Titano- 

 therium and overlying Oreodon beds was rewarded with greater 

 success, for numerous thin layers of limestone, varying in thickness 

 from a fraction of an inch to a foot or more and always of limited 

 areal extent, were discovered at many horizons rich in the remains 

 cf fresh-water plants and mollusca, such characteristically shallow- 

 water forms as Chara, Limnaea, Physa and Planorbis occurring in 

 the greatest abundance. I have submitted these mollusca to Drs. 

 Dall, Pilsbry and Stanton, and all have assured me that they belong 

 to species inhabiting swamps and small ponds, and could not have 

 lived in the midst of a great lake ; while Dr. Knowlton, who has 

 examined the plants, finds in great abundance the stems and seeds 

 of Chara, which, as all know, is distinctly an inhabitant of small 

 springs, shallow ponds and brooks. The presence of these thin 

 limestone layers with such characteristically swamp plants and 

 mollusca as are Chara and Physa at various horizons throughout the 

 White River series, and in the very midst of the region which was 

 supposed to have been occupied by a great lake, and intercalated 

 with the clays which advocates of the lake theory maintain were 

 deposited in the deep and quiet waters, would appear to preclude 

 the possibility of the existence of such a lake in White River 

 times. Moreover remains of forests were found at several places 

 and at different horizons throughout these beds. At various locali- 

 ties in the Hat Creek basin in Sioux County, Nebraska, I discov- 

 ered remains of the silicified trunks of trees and seeds belonging 

 especially to Hickoria and Celtis. These were found at various 

 horizons from the middle Titanotherium beds to the very top of the 

 Loup Fork. And in South Dakota, some twelve miles north of 

 White River, opposite the mouth of Corn Creek, I discovered the 

 remains of a no inconsiderable forest. Here in the upper Titano- 

 therium beds and lower Oreodon beds there occur, actually by 

 hundreds, the silicified stumps and partially decayed trunks of trees, 

 weathering out of the fine clays of these deposits. It was notice- 

 able that only the knots and lower stumps had been preserved. 

 Nothing like complete trunks were to be observed, and the entire 



