RECENT ADVANCES IN SCIENCE 553 



tute of Washington, entitled Papers from the Department of 

 Marine Biology (vol. ix. 191 8), contains much geological 

 material relative to the origin of marine sediments, particu- 

 larly limestones. A very complete study of calcareous bottom 

 sediments, chiefly from Australian and Floridan localities, has 

 been made by T. W. Vaughan and his collaborators (pp. 239- 

 88), and includes the consideration of the following subjects : 

 mechanical analyses ; study of the composition of the separates 

 of different sizes and the determination of the percentage 

 composition of each separate according to the origin of its con- 

 stituents ; the chemical composition of each constituent ; the 

 chemical composition of the entire sample ; the correlation of 

 the chemical composition of the entire sample with that of its 

 different constituents according to their percentage ; the 

 conditions under which the deposit is formed, viz. its rela- 

 tions to land areas, the configuration of the bottom, winds, 

 and currents, and the depth, temperature, and salinity of the 

 water in which formed ; the areal extent, and if possible the 

 volume of the deposit. 



M. I. Goldman has made a detailed study of thirteen sedi- 

 ments from the Upper Cretaceous of Maryland (Maryland 

 Geol. Surv. 1916, 11 1-84). These are all of shallow marine 

 origin, and are classed as deltaic, estuarine or lagoonal, or 

 of open water glauconitic type. An illuminating discussion of 

 the occurrence and origin of glauconite is appended. 



A. M. Phillips discusses the discovery of a small percentage 

 of vanadium in the ash of a brown holothurian (Slicopus 

 mobii) and in the blood of an ascidian ; and the possibility 

 of the vanadium found in certain sedimentary rocks originat- 

 ing from similar organic sources (Amer. Journ. Sci. i9 J 8, 46, 



473-5). 



For the explanation of the remarkable zig-zag suture-like 



lines in the Tennessee and other marbles and limestones, 



known as stylolites, C. H. Gordon (Journ. Geol. 191 8, 26, 



561-8) prefers the solution theory proposed by Fuchs in 1894 



and later supported by Reis and Wagner, to the differential 



compression theory first advocated by Quenstedt. 



The huge deposits of phosphate rock in the western United 



States belong to horizons in the Upper Mississippian and 



Permian, of which the latter is by far the more extensive. 



They are regarded by G. R. Mansfield (Amer. Journ. Set., 1918, 



