IZ A TREATISE ON THE C NNECTION OF

There are different kinds of such simple, or, as they are| frequently called, primary earths; those which generally Occur, and principally regard the object of this Treatise, are, Calcareous, or chalky; argillaceous, or clayey; sili-| ceous, or sandy; and magnesian. It is also necessary to mention, that the earth of iron is likewise contained

in Most soils, in great abundance;€Xisting therein, in various states,

|

CALCAREOUS MATTER

ee

CONSTITUTES not only the surface, or soil, but Jike-

wise the under stratum of many

t it i 7} i

countries, to avery great

depth. Under this general name of calcareous matter

is included chalk, marble,

est Gee

limestone, coral, shells,&c,

The three first mentioned are frequently mixed with

iron, and with different Proportions of the simple earths;

but are considered as calcareous, when the Proportion of

that earth predominates, It is capable of absorbing, and

of