74 The American Geologist. February, ism; 
iiparite, andesite and basalt. Andesite covers a great stretch 
of country about the head of Owen's river, forming the cresl 
of the Sierra Nevadas between it and the head of the north 
fork of the San Joaquin river. 
The writer expects to describe the microscopic characters 
of the rocks of this region in a subsequent paper. 
THE ASSOCIATION OF THE GASTEROPOD GENUS 
CYCLORA WITH PHOSPHATE OF LIME 
DEPOSITS. 
By Arthur M. Miller, Lexington, Ky. 
The interest aroused by the discussions concerning the 
nature and origin of the phosphate deposits of Tennessee led 
to the carrying on of some investigations in the laboratory of 
the Kentucky Agricultural Experiment Station with a view 
towards throwing more light upon the subject. The speci- 
mens selected for examination were from three different 
localities, representing three different geological horizons, as 
follows : 
Phosphate rock, bottom of Devonian black shale, Tennessee. 
Limestone, lower Hudson River, Covington, Kentucky. 
Phosphatic layers, top of Trenton limestone, Lexington, Kentucky. 
All exhibited specimens of Cyclora (probably C. minuta 
Hall) in great abundance, but the Covington specimen only 
showed them upon the surface of the rock. The plan was to 
analyze the rock as a whole and then a weighed number of 
the fossil shells (casts) separately, and compare the percent- 
ages of phosphoric acid and lime phosphate obtained. The 
Devonian and Hudson River specimens of Cyclora could be 
readily picked out from the rock with the aid of a lens, but 
the Trenton forms would not admit of this. It was found 
possible, however, to apply the tests for phosphoric acid 
directly to the shell casts themselves as they lay embedded in 
this^rock, and the results thus obtained were as satisfactory 
as in the two other c;iscs. indicating that the phoshate of 
lime was confined to the casts. 
The analyses were made by Dr. Alfred M. Peter, chemist of 
the Experiment Station, who also first directed the writer's 
