224 On the Topography and Soil of Parts. 
river was swollen beyond its ordinary dimensions. The 
gravel which it carried with its stream and the mud*which 
it kept suspended after great rains were deposited on the 
surface of the meadows, and every year a new layer of these 
deposits raised the soil, while at the same time repositations 
of asimilar nature raised the bed of the river; thus the 
bottom of the river and the soil of the meadows would 
have continued to rise nearly simultaneously, by the de- 
posit of the substances which the Seine brought from the 
higher grounds, if the necessity of warding off the effects 
of inundation bad not compelled the first inhabitants of 
the small island of Lutece, and those who subsequently 
came to inhabit the two opposite banks of the Seine, to ac- 
celerate the work of nature by bringing new accessions of 
soil to the grounds which they occupied, by raising on the 
banks of the river either dykes or quays to defend them 
from its encroachments. 
It was therefore at the earliest period in the history of 
Paris that the soil on which it was situated began to be 
raised artificially, and since this period the bed of the Seine 
hasbeen slowly rising; but from the natural effect of a cause 
always acting, which raised at the same time the level of the 
jnundations, it became necessary, to provide against the 
latter, to raise the Jevel of the quays and grounds adjoining 
by adding loads of earth in proportion, 
As this labour is confined to heaping up rubbish on one 
point of the valley rather than on another, it seems foreign 
to the subject of geology : besides, the small number of facts 
which history has transmited asto the changes which have 
brought the materials of the soil of Paris to their present 
state, have been collected accidentally only, and are counect- 
ed it) some measure with circumstances of another nature. 
While Paris was a fortified city, surrounded by ditches 
and walls, the materials which proceeded from the daily 
demolition of the ancient edifices, which were replaced by 
new buildings, could not be permitted to remain within the 
walls: the narrowness of the streets and the height of the 
houses, in the more ancient parts of the town, sufficiently 
prove that the ground was too precious to dedicate any part 
of it to the storing up of rubbish, which was taken outside 
of the walls, and deposits of it formed near to the principal 
gates. , 
In this manner were formed outside of the two great cir- 
cumvallations of Paris,made in the reign of Philip the August 
and Charles LX., the mound Saint Roch, or des Moulins, 
between the ancient gates of St. Honoré and Mont Martre; 
the 
