PREFACE. Vil 
undergone, and the figures will be done in such a 
way as to help the description as much as may be, 
with the shining pearly stony or metallic brilliancy. 
Many species of one genus may be included in a 
plate, as it might be thought insignificant to figure 
a single small Shell alone. I have long since pos- 
sessed a tolerable collection of British Fossil Shells. 
To the addition of a fine series from Highgate, by 
favour of my indefatigable friend B. G. Snow, Esq. 
may be attributed my more particular attention to 
this branch of Natural History. I here beg leave 
to thank him and other kind friends for the many 
specimens received, and hope the present under- 
taking will meet their approbation. 
JAMES SOWERBY. 
