Definify.com
Webster 1913 Edition
Greensand
Green′sandˊ
(-săndˊ)
, Noun.
(Geol.)
A variety of sandstone, usually imperfectly consolidated, consisting largely of glauconite, a silicate of iron and potash of a green color, mixed with sand and a trace of phosphate of lime.
☞
Greensand
is often called marl
, because it is a useful fertilizer. The greensand beds of the American Cretaceous belong mostly to the Upper Cretaceous.