226 On the Recent Discovery of Flint Implements 
can therefore throw but little light upon the state of our 
county during that period. This page in the book of nature is a 
blank—partly from the probable manner of its formation, but 
much more so from the loose porous character of the deposit 
which is unfavourable for the preservation of organic structures. 
On the other hand, the fine soft mud of the Fisherton brick-fields, 
embalmed, and bears most interesting record of the many strange 
wild creatures which formerly inhabited our peaceful valleys, and 
roamed over our chalk downs. | 
That the Fisherton brick-earth was deposited in comparatively 
tranquil water is abundantly testified by its semistratified character, 
and also by the presence of a number of freshwater and land shells 
as seen in the subjoined list. 
FRESH-WATER SHELLS. Lanp SHELLS. 
Ancylus fluviatilis. Succinea putris, 
Lymnea truncatula. » elegans. 
» palustris, * 4, oblonga. 
»>  limosa. Helix arbustorum. 
Planorbis spirobis. 5)  nemoralis. 
»  earinatus. »  pygmea. 
Bithynia tentaculata, »,  pulchella, 
Valvata piscinalis, »,  rufescens. 
Pisidium amnicum. »» hispida. 
i pulchellum. mr do., var. concinna 
no do., yar. (Jenyns.) »  rotundata, 
"1 pusillum. »  fulva. 
5} obtusale Zonites radiatulus. 
Pupa muscorum. 
Zua subcylindrica. 
Carychium minimum, 
Acme lineata. 
Limax agrestis. 
* This is the only Shell not now found in this neighbourhood. 
Many of these shells are extremely fragile, and yet they are 
found in a beautifully perfect condition, the very valves of the 
delicate little Pisidia remaining unseparated, although the con- 
necting hinge ligament had, from the great lapse of time, long 
1The nomenclature in this list has been adopted from Reeve’s ‘‘ Land and 
Freshwater Mollusks,” 1863, in order that it may accord with the catalogue of 
Wiltshire shells, by the Rey. J. E. Vize, in vol. i of the Wiltshire Magazine. 

