Chap. 4.] 
EIGHT KIKDS OE EAETH. 
453 
Gaul and Britain, of enriching earth by the agency of itself, 
being ^' ^ * and that land known as mari."^"* 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"^^ 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'^ 
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'^''' 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,^^ consisting of stones mingled with a thin sandy 
A natural mixture of argilla and calcareous stones, or subcarbonate of 
chalk. 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. 
'^^ 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. 
The Marga terrea of Linnjeus. It abounds in various parts of 
Europe. 
7^ From the Greek, meaning " not bitter marl." 
