John Morton 
On the Nature and Property of Soils Their Connexion With the Geological Formation on Which They Rest, the Best Means of Permanently Increasing Their Productiveness, and on the Rent and Profits of Agriculture [PDF ebook] 

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. The surface of the earth partakes of the nature and colour of the subsoil or rock on which it rests.<br><br>The principal mineral in the soil of any district, is that of the geological formation under it; hence, we find argillaceous soil resting on the various clay formations — calcareous soil, over the chalk, and oolitic rocks, and silicious soils, over the various sandstones. On the chalk, the soil is white; on the red sand stone, it is red; and on the sands and clays, the surface has nearly the same shade of colour as the subsoil.<br><br>The lime, potash, and iron, existing in various proportions in the rock, are acted on by the atmosphere, and the rock is decomposed; some of it into fine impalpable matter, some into sand, and some into coarse gravel or rubble.