Geology and Mineralogy. 



the Sevier and Salt Lake basins, it was separated into two unequal 

 portions. In one of these the evaporation exceeded the inflow 

 from rivers, and the subsidence continued ; in the other the inflow 

 exceeded the evaporation and the surplus was discharged over the 

 divide into the former portion, just as the surplus of Utah Lake is 

 now discharged into Great Salt Lake. In the course of time, as 

 the climate became drier, this overflow ceased ; but not until it 

 had carved a channel of some magnitude. The channel is crossed 

 by the old overland stage road, and is known as " the Old River 

 Bed." It is doubtless this ancient water-way which has been 

 described to Mr, Packard. I am not aware that it has ever been 

 determined whether the channel slopes toward Sevier, or toward 

 Great Salt Lake ; but a consideration of the forms and dimensions 

 of the two basins, and of the present relative salinity of the two 

 lakes, leads to the belief that it was the Sevier Basin which over- 

 flowed into the other. The summit of the divide cannot be far 

 above the present level of Sevier Lake. 



In the early part of the field-season of 1872, I crossed the Salt 

 Lake and Sevier deserts as a geologist of the Wheeler Expedition, 

 and gave especial attention to the beaches and other phenomena 

 of the ancient lake. Later in the season my associate, Mr. 

 Howell, carried the observations farther south. Our examinations 

 were sufliciently thorough to enable us to draw a map of the 

 southern half of the old lake, but we found no evidence of an 

 outlet in that direction, although we made diligent search. Ac- 

 cording to the conjecture of Professor Bradley, and the unpub- 

 lished observation of Professor Marsh, the overflow was north- 

 ward, and the Columbia River carried the water to the ocean. 

 There assuredly was an overflow. 



In the progress report of Lieut. Wheeler's Surveys for 1872, 

 I have expressed the opinion that the hiimid climate which was 

 marked by this inundation of Utah, was preceded by one as arid 

 as the present ; and that the humidity was a phenomenon of the 

 Glacial Epoch. A fuller statement and discussion of the facts 



^ , and the accompanying i 

 a map of the ancient lake. 



3. Second Report of Progress of the Miner alogical, Geological 

 and Physical Survey of the State of Georgia, for 1875; by 

 (teobge Little, State Geologist. Bvo, 16 pp.— This brief report 

 shows a large amount of work done during the past year. The 

 several parties have travei-sed, in all, over 6,000 miles of road, 

 making careful examinations and large collections along their 

 routes. They have visited 105 out of the 137 counties in the State, 

 and a list is given of the minerals, metals and building-stones, of 

 economical value, which have been found in 76 of these counties. 



Under the head of Geology, Dr. Little says : " In the North- 

 western portion of the State, the coal-formation has been found, 

 l>y ^Ir. McCutchen, to be somewhat more extensive than observed 



