ORGANISMS FROM THE RECENTLY DISCOVERED ROMAN BATH, 193 
of the Roman occupation, is clearly shown. It appears that on the 
departure of the Romans the country lapsed into its primitive state ; 
the bed of the river, no longer kept in order, became dammed 
up by fallen trees, landslips, and the like, and the place where 
a high civilisation had existed became a shallow lake. The 
torrential streams of winter washed down from the neighbouring 
hills the surface-mould and decaying vegetation into the bottom of 
the valley, where it became deposited as mud, of which it formed 
successive layers, mixed with the river sediment and the fresh 
water shells. As a considerable portion of the strata of the hills 
around Bath consists of ‘ Fuller’s earth’ it is probable that much of 
the firm mud, which appears to be from five to six feet thick, was 
derived from the washing, by rain, of the ‘ Fuller’s earth’ slopes. 
The continuance of this deposit was certainly prolonged : as the 
quantity of matter deposited in any single year must be represented 
in its now compressed form by a very thin layer. Eventually these 
deposits ceased, and then the surface became adapted for the 
growth of rushes, in fact, it became a morass, and this condition of 
things prevailed long enough to allow of the deposit of decayed 
rushes to the depth of two feet. At the close of this period 
the river bed appears to have been cleared of its obstructions, 
probably by the hand of man, as the bed overlying the rush 
deposit is of artificial origin ; the works of civilisation were again 
resumed and the surface of the river valley underwent a corres- 
ponding change. It is difficult, without personal examination, to 
describe with accuracy the physical changes that took place and which 
led to the formation of these deposits, but in all the river valleys of 
this part of the country, where the current is not very rapid, there 
must occur in the natural condition of things obstructions of the 
nature of those I have suggested as having occurred at Bath. In 
the valley of Frome, near Stroud, there are many flat meadows 
which owe their origin to similar conditions. The section is 
interesting inasmuch as it shows that a state of change still exists, 
that the operations of nature, under which the surface of the high 
lands is being denuded, are still going on, and where, as in the 
present instance, some of the results are capable of measurement, 
they are shown to be neither slight nor unimportant.” 
Beyond this opinion a large amount of interest centres in the 
probability that at one time the tide flowed up the river as far 
as the site of the bath. I am greatly indebted to Mr. Rimmer, 
F.L.S., of London, whose admirable recent book on ‘“ The Land 
and Fresh Water Shells of the British Isles” enabled me to corres- 
pond with him. He has not only been kind enough to complete 
the naming of the shells, which I shall presently show and describe 
to you, but he calls attention to one species which I found, not in 
the mud bank, but mixed with the sand and soil of the ambulatory 
