ON COLLECTING FOSSIL SHELLS. 44] 
I have reserved for especial mention in this place, the 
work, which will afford the student of British fossil Con- 
chology the most important aid in the identification of spe- 
-cimens, namely, the “ Mineral Conchology of Great Britain,” 
by the late eminent naturalist, Mr. James Sowerby, and 
continued by his son, Mr. James De Carle Sowerby ; in six 
volumes 8vo., with several hundred coloured plates. Unfor- 
tunately, this work has long been discontinued ; and the 
rapid progress of discovery, and the numerous foreign pub- 
lications on every department of fossil conchology, almost 
forbid the hope that it will be resumed by the present pro- 
prietor. Although the high price of this work places it 
beyond the reach of many individuals, it will be found in 
most libraries of Natural History. 
On THE COLLECTION AND ARRANGEMENT OF FossiL SHELLS. 
—The instructions already given for the collection of corals, 
echinoderms, &e., will have familiarized the student with the 
methods generally adopted, and render it unnecessary to 
enter into much detail. The shells in arenaceous deposits, 
particularly in those of the Tertiary formations, are com- 
monly so perfect, as merely to require careful removal : 
those in the clays are more fragile, and must be extracted 
with great caution ; and, when very delicate, should be left 
attached to the clay or shale. The specimens extracted 
entire may be kept either in paper trays, lined with wadding, 
or fixed to pieces of card or thin board covered with paper, 
by thick gum-water ; three or four specimens being attached 
in different positions, so as to expose the essential characters, 
as the aperture, spire, and back of the univalves, and the 
hinge, muscular imprints, &c. of the bivalves. Where only 
casts remain, search should be made for an impression of the 
outer surface of thé shell, and a cast taken of it in wax, 
kneaded bread, or plaster of Paris. In indurated clays, some- 
times both shells and casts may be obtained ; and a specimen 
