422 
THE GEOLOGIST. 
From the humblest cottage to the stateliest mansion the beautiful 
shells of ocean depths are treasured oniaments ; and, unless it be 
flowers, few things, if any, as a class arc more beautiful. Pearly in 
structure, exquisitely marked and colour-painted, often elegant in 
form, they are worthy natural ornaments to be prized and treasured; 
whether some son, brother, father has brought them after long 
voyages from distant parts, or some child had picked them off the 
neighbouring strand. 
So common and so homely are our associations with shells that 
the first trace of them in the stony strata of our earth strikes us with 
more than usual interest. Somehow, one seems to regard them as 
old acquaintances, as something familiar and not strange, as some- 
thing that brings back our childish feelings to our scathed and 
hardened hearts, and makes us for the moment gentler than in the 
stern fight of life we are wont to be. 
Lign. 6. — LiNGcxA Davisii (nat. 
size). From the figuro in the 
" Synopsis of British Palaeozoic 
rossils," by Sedgwick and 
McCoy. Plate i., L, fig. 7. 
Prom a specimen from elates 
south of Penmorfa. 
Yet in those first fossil shells we recognize the mollusc-type. 
Shells very like them, very like indeed, still exist, but deep down in 
the sea and afar oS". One very rarely sees any, and then only in the 
cabinets of the curious, for they are small simple dark horny shells 
and not attractive, and the antique fossils, crumpled and distorted as 
they mostly are, in their glistening blackness outvie their modern 
dusky representatives. Wonderful indeed are the varieties of mark- 
ings and forms of the two simple valves inclosing the symmetrical 
mollusca. A pair of shells held together and pressed open at one 
and the same time by a tenaceous, elastic hgament, would scarcely, 
one would have imagined, have afforded much room for diversity of 
structure or shape ; but thousands of distinct and living species have 
been examined, and recorded by naturalists. Every ship returning 
from new and distant parts is daily adding to the extensive cata- 
logue, while the fossil species are not inferior in number to the recent. 
But it is not in mere outline or shape alone their characters are 
