CONARD-FISSURE GROUP 123 



Particular attention will be given to any data bearing on the 

 climate and conditions of life in that region when the Uintatheres 

 and hornless Titanotheres, Four-toed Horses, primitive Rhinoce- 

 roses, carnivores, rodents and insectivores inhabited it, and 

 on how their remains came to be entombed in the rock strata 

 where they are found. It has already been discovered that the 

 Bridger formation is derived from volcanic ashes, so that active 

 volcanoes must have existed at no great distance. This may 

 be at least partly true of the other Eocene formations also. It 

 is probable, too, that the climate was then very different 

 from that of the present day, and the height of the region 

 above sea-level much less than now. 



The third expedition under Mr. Albert Thomson will search 

 the later Tertiary formations of South Dakota for fossil mammals 

 and especially for Three-toed Horses. Previous explorations in 

 this region and elsewhere have shown that there was a great num- 

 ber and variety of Three-toed Horses in America during the later 

 Tertiary epochs, but most of them are incompletely known and 

 the problem of the direct ancestry of the modern Horse is not yet 

 satisfactorily solved. Doctor Matthew and Mr. Gregory will join 

 the expedition during a part of the season and Professor Osborn 

 hopes to be with Mr. Brown's party in Montana for a short time. 



THE CONARD-FISSURE GROUP 



HE Department of Vertebrate Palaeontology has 

 placed on exhibition in its hall a model of the 

 Conard Fissure in northern Arkansas, an open 

 crack formed by small upheavals of the earth's 

 surface, in which have been found great numbers 

 of fossil bones. The fissure is located in the forest-covered Ozark 

 Hills about fifteen miles south of the town of Harrison. During 

 the Pleistocene epoch it was open and was inhabited by large and 

 small carnivorous animals, such as the bear, tiger and weasel, 

 and by rats, mice, birds and snakes, the bones of which, to- 

 gether with those of other beasts which they had dragged into 

 their lairs to devour and gnaw at leisure, were buried in the 

 earthy and stony accumulations. About 10,000 skulls, jaws and 



