422 THE GEOLOGIST. 



From the humblest cottage to the stateliest mansion the beautiful 

 shells of ocean depths are treasured ornaments ; and, unless it be 

 flowers, few things, if any, as a class are 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.— LiNGULA Davisii (nat. 

 size). From the figure in the 

 " Synopsis of British Paleeozoic 

 Fossils," by Sedgwick and 



MoCoy. Plate i., L, fig. 7, 

 From a specimen from slates 

 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 ofi". 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 

 moUusca. A pair of shells held together and pressed open at one 

 and the same time by a tenaceous, elastic ligament, would scarcely, 

 one would have imagined, have afibrded 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 outhne or shape alone their characters are 



