110 REPORT OF ELLWOOD C. PERISHO, STATE GEOLOGIST 



pictograph writings showed plainly and drawings were taken for 

 future reference. 



Mr. Barthold Iverson did some valuable field work for the 

 Survey in the eastern part of the state upon the artesian well 

 problem. 



The State Geologist has spent a limited amount of time in 

 field work in the northwest part of the state making a study of 

 the general geology with special reference to the lignite coal beds. 

 Also in the Southern Black Hills, principally upon the mica and 

 lithia ore formation. A valuable mineral collection was added to 

 the Museum by this trip. He has also made many observations 

 and collected data concerning the Artesian water supply for 

 eastern South Dakota. 



Wm. H. Over devoted the summer to field work. The month 

 of June was spent upon the fauna and flora of Clay County. 

 Some four hundred plant specimens were obtained. Special at- 

 tention was paid to the collecting of grasses of this locality. Many 

 specimens of Reptiles, Amphibians and Mollusks were taken. 



During July, August, September and part of October Mr. 

 Over was camping at different localities in the southwestern part 

 of Stanley County, Washabaugh and Lawrence Counties. In 

 Lawrence County about four hundred plant specimens were pro- 

 cured, forty-five 'species being new to our Black Hills collection. 



In Stanley County the time was occupied in the Badlands 

 collecting fossils, however, nothing of interest in geology or bio- 

 logy was neglected. Perhaps the most valuable specimen collected 

 was an almost complete fossil skull of the ancestral rhinocerous, 

 (Caenopus Tridactylus) found in the Oligocene formation. This 

 was found embedded in a sandstone layer. Later it was worked 

 out of the sandstone matrix and is now on exhibition in the Bad- 

 land fossil case. 



A number of specimens of fossil Turtles were found, two of 

 which are new to our Museum collection of turtles. 



The skull of a fossil Elotherium was found in the Oligocene. 

 This mammal was about the size of, and perhaps allied to the 

 ancestral hog. A new species of Helix, a fossil land shell, was also 

 found. 



Many teeth and parts of a skeleton of the fossil Mesohippus 

 bairdi, or ancestral three toed horse, were collected and much 



