128 ALLUVIAL LANDS. 
lowness of the ground from Catwater onwards to 
the bottom in which the above named Church oc- 
curs, is the very manifest reason why so large a 
volume of water reposed there in former years. St. 
Germains was a cotemporary small emporium of 
the Romans together with Plympton, and their 
vessels were enabled to penetrate as far up as the 
Castle ;—this circumstance is consistent with the 
flatness of the country from Hamoaze upwards to 
the town, and at this day, like the former case of the 
Lara, the river St. Germains is reduced to a much 
less considerable size. In other directions how- 
ever where no such extensive flats occur, evidences 
are yet found of retreat on the part of estuaries pass- 
ing up between closely approximating hills. The 
Rey. J. Yonge has kindly written me the information 
that he bored close tohis house in Puslinch meadow 
to the depth of 40 feet, “‘ and brought up black mud 
anevidentdeposit.” Thismeadow is some little way 
from the limits of the estuary as it now stands, (or 
would stand if not restrained by an embankment) 
and the circumstance brought to light by Mr. Y. 
marks the retreat which has been progressively 
taking place in modern times. | 
Alluviallands indeed, are altogether greatly on the 
increase, and the Erme river seems to me to indicate 
this fact conspicuously both by accumulation of mud 
inthe smaller branches, and by the bulk of sand cast 
up by the sea towards its mouth. Its possession 
of a “ bar” or bridge of rocks at the entrance greatly 
favors this collection, since, the quantity which the 
tide in ordinary cases conveys with it on its 
retreat, is here at once retained after its first in- 
troduction. The Exe furnishes an example of the 
same kind, owing to the existence of a “ bar” there 
also, while the Dart having none, is enabled to 
cleanse its bottom on each egress of the tide, and 
the river altogether affords excellent ground for | 
