80 BLUE CHALK MARL. 



II. 5. BLUE CHALK MARL. 



Syn. — Micaceous brick earth. Smith's Strata, p. IS. 



Gait of Cambridgeshire. Geological Transactions, Vol. 5. p. 114. 



Folkestone marl. Phillips' Outli^ies. 



Malm rock. Hawkins' Memoir. History of Sussex, Vol. 2. p. 114. 



This deposit consists of a stiff marl of a greyish blue, brown, or ferru- 

 ginous colour. It contains nodular masses of indurated marl, and thin 

 layers of a reddish brown schistose limestone. In western Sussex the 

 beds afford good building stone. 



The blue marl reposes upon the green sand, its basse ting edge inter- 

 vening between the outcrop of the latter, and the northern escarpment of 

 the chalk hills. The denuded surface of this bed forms a soil remarkable 

 for its tenacity, and which, in many parts of Sussex and Surrey, is di- 

 stinguished by the provincial term, " black land :" it is thus described by 

 Mr. Young: " At the northern extremity of the Downs, and usually ex- 

 tending the same length, is a slip of very rich and stiff arable land, but of 

 very inconsiderable breadth ; it runs for some distance into the vale before 

 it meets the clay. The soil of this narrow sHp is an excessively stiff cal- 

 careous loam, on a clay bottom ; it adheres so much to the share, and is so 

 very difficult to plough, that it is not an unusual sight to observe ten or 

 a dozen stout oxen, and sometimes more, at work upon it. It is a soil 

 that must rank amongst the finest in this, or any other country, being pure 

 clay and calcareous earth*." It generally occupies low situations, and 



* Ymings Agricultural Survey of Sussex. 



