56 The Bad land Formations of the Black Hills Region 



conditions commonly resulting from an advancing lake margin 

 such as a basal conglomerate or other water sorting features. 



Paleontoldgic Bvidence. First, the fauna of the clays is a 

 land fauna. Remains of land animals as we know them and as 

 the necessity of the case seems to demand are seldom or never 

 found in abundance in open lake sediments. In the badland 

 clays land animal remains are often excessively abundant and 

 furthermore constitute the whole of the fauna. The clays are 

 entirely free from fishes and such invertebrates and reptiles and 

 mammals as might be expected to have lived in lake waters 

 of that time. The sandstones likewise are deficient in aquatic 

 life, but they do occasionally contain fishes and crocodiles and 

 in one locality abundant unios (mussel shells) were found. 

 Mr. J. B. Hatcher, in 1900 and 1901, in making a careful 

 study of the Titanotherium and Oreodon beds found within 

 the clays numerous thin lenticular limestones varying in thick- 

 ness up to twelve inches or more which contained in abundance 

 characteristic shallow water plants and mollusks such as live 

 in fresh water swamps and small ponds and whfch could not 

 have lived in the midst of a great lake. Furthermore, Hatcher 

 at several places in the clays found marked evidence of land 

 vegetation. He says, "At various localities in the Hat Creek 

 basin, in Sioux County, Nebraska, I discovered remains of 

 Hickoria and Celtis. These were found at various horizons 

 from the Titanotherium beds to the very top of Loup Fork. 

 And in South Dakota, some twelve miles north of White 

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

 remains of no inconsiderable forest. Here in the upper 

 Titanotherium beds and the 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 noticeable that only the knots and lower stumps 

 had been preserved. Nothing like complete trunks were to be 

 observed, and the entire 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 suf- 

 ficiently 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 vegetable mould or 

 humus, and on Dry Creek, some five miles northeast of Chad- 

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

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



