484 Journal of Agricultural Research voi.xv, no- 



fertilizers were introduced the use of these marls quickly fell off. At 

 the present day they are practically neglected. 



DISTRIBUTION AND NATURE OF GREENSAND DEPOSITS 



These deposits occur most abundantly in the Atlantic coastal plain 

 lying on the seaward side of the "fall line," where they are oftentimes 

 extensively exposed by the rivers which cut this line. The most impor- 

 tant greensand deposits of the eastern States extend from Navesink 

 Heights near Red Bank, N. J., in a southwesterly direction to a region 

 below the James River southeast of Richmond. 



The materials vary in appearance from greenish black when the 

 greensand is fairly pure to a grayish color, which is determined by the 

 proportion of shells and sand present. Greensand (glauconite) can 

 usually be demonstrated as small rounded grains, black or greenish in 

 color, present in the earth embedding the shells as a matrix and filling 

 the hollows of the shells. The grains leave a green streak when rubbed 

 on hard paper with a knife blade. 



Especially prominent in many Virginia deposits is an overlying layer 

 of somewhat different character, called by Edmund Ruffin "olive earth." 

 This material, while not a greensand deposit, must be considered prac- 

 tically as a part of it, since it must usually be dealt with before the 

 underlying greensand deposits can be reached. These olive earths 

 frequently contain sufficient quantities of calcium carbonate and phos- 

 phates to give them considerable value. 



CHEMICAL COMPOSITION OF GREENSAND DEPOSITS 



Typical deposits from both New Jersey and Virginia were collected 

 for this work and analyzed with special reference to the constituents 

 generally recognized as having major importance for plant growth.* 

 The materials used in the culture experiments reported below gave the 

 results seen in Table I. 



' Mr. Otis F. Black, Chemical Biologist, and Mr. James W. Kelly, Chemical Technician, of this Office, 

 made the analyses. 



