Abstracts 89 



PHOSPHATE ROCKS OF JOHNSON COUNTY, TENNESSEE. 



BY OLAF P. JENKINS, STATE GEOLOGICAL SURVEY. 



(A hstract.) 



The recent discovery and primary development of phosphate rock 

 in Johnson County has exposed some new and interesting scientific 

 problems and may later prove to be of economic importance. A 

 chemical and mineralogical study of the material found, in connec- 

 tion with the field work, shows that the phosphate rock in this re- 

 gion is formed usually as a secondary concentration in residual 

 brecciated rocks which were originally limestone. The geological 

 horizon for the phosphate is apparently the upper beds of the Shady 

 limestone and the lower beds of the Watauga shale of Keith's no- 

 menclature. (Published in "Resources of Tennessee," Vol. VI, 

 No. 2.) 



November 26, 1915. 



RECENT RESULTS IN MATHEMATICAL ASTRONOMY. 



BY H. E. BUCHANAN, UNIVERSITY OF TENNESSEE. 



(A bstract.) 



The purpose of this paper is to present in non-technical language 

 the results attained in some recent papers on the Problem of Three 

 Bodies. Only a part of these results are due to the author, but they 

 are all closely connected. No mathematical formula is used, and 

 it is hoped that the statement of the problem and the results ob- 

 tained are made interesting to scientists in other lines of work. 



November 26, 1915. 



THE EVOLUTION OF MISSISSIPPI RIVER CRAFT AS INFLU- 

 ENCED BY GEOGRAPHIC CONDITIONS. 



BY CHAS. C. COLBY, GEORGE PEABODY COLLEGE FOR TEACHERS. 



(Abstract.) 

 This paper deals with the geographic factors which brought about 

 an evolution in the type of boats used in the successsive periods of 



