Chap. 4.] EIGHT KINDS OF EAETH. 453 



Gaul and Britain, of enriching earth by the agency of itself, 

 being # * .# * and that kind known as marl. 74 This 

 soil is looked upon as containing a greater amount of fecun- 

 dating principles, and acts as a fat in relation to the earth, just 

 as we find glands existing in the body, which are formed by a 

 condensation of the fatty particles into so many kernels. 

 (7.) This mode of proceeding, too, has not been overlooked by 

 the Greeks ; indeed, what subject is there that they have not 

 touched upon? They call by the name of leucargillon 75 a 

 white argillaceous earth which is used in the territory of 

 Megara, but only where the soil is of a moist, cold nature. 



It is only right that I should employ some degree of care 

 and exactness in treating of this marl, which tends so greatly 

 to enrich the soil of the Gallic provinces and the British islands. 

 There were formerly but two varieties known, but more re- 

 cently, with the progress of agricultural knowledge, several 76 

 others have begun to be employed ; there being, in fact, the 

 white, the red, the columbine, the argillaceous, the tufaceous, 

 and the sandy marls. It has also one of these two peculiar- 

 ities, it is either rough or greasy to the touch ; the proper 

 mode of testing it being by the hand. Its uses, too, are of a 

 twofold nature — it is employed for the production of • the 

 cereals only, or else for the enrichment of pasture land as 

 well. The tufaceous 77 kind is nutrimental to grain, and so 

 is the white ; if found in the vicinity of springs, it is fertile 

 to an immeasurable extent ; but if it is rough to the touch, 

 when laid upon the land in too large a quantity, it is apt to 

 burn up the soil. The next kind is the red marl, known as 

 acaunumarga, 78 consisting of stones mingled with a thin sandy 



74 A natural mixture of argilla and calcareous stones, or subcarbonate of 

 cbalk. Fee remarks, that the ancients were not acquainted with the 

 proper method of applying it. Marl only exercises its fertilizing influence 

 after being reduced to dust by the action of the atmosphere, by absorbing 

 the oxygen of the air, and giving to vegetation the carbonic acid that is 

 necessary for their nourishment. 



75 '' White argilla." This, Fee thinks, is the calcareous marl, three 

 varieties of which are known, the compact, the schistoid, and the friable. 



76 At the present day there are only two varieties of marl recognized, the 

 argillaceous and the calcareous ; it is to the latter, Fee thinks, that the 

 varieties here mentioned as anciently recognized, belonged. 



77 The Marga terrea of Linnaeus. It abounds in various parts of 

 Europe. 



7& From the Greek, meaning "not bitter marl." 



