12 SHELLS AND SHELL-FISH. PART I. 



than is to be found among their animals ; hut these 

 latter must be well studied^ before we can comprehend 

 the leading types of form prevalent among the former. 

 When this last discovery, if only in part, has been 

 made, we shall find that the slightest modification in 

 the shell is not without its meaning; and that, in nine 

 instances out of ten, we may pronounce with as much 

 confidence on its natural station in the scale of nature, 

 as if we had actually dissected its animal. 



(12.) A singular idea appears to be entertained by 

 some writers, that the '^'^art" of conchology, popularly 

 so called, is only really serviceable to science, when 

 viewed in connection with geology. But it may 

 fairly be asked, how geology or any other branch of 

 knowledge can be benefited by any aid which is not, in 

 itself, built on sound and philosophic principles, which 

 this " art " confessedly is not. It would be difficult to 

 answer the question why one branch of zoology is to be 

 separated from the others, and degraded into the hand- 

 maiden of another science, — and that, too, of such very 

 recent formation, that the most opposite opinions as to 

 its very first principles are continually issuing from the 

 press. It is not a little singular, also, that, while 

 geologists appear to attach so much importance to 

 mineral conchology, as it is termed, no author, as yet, 

 has specifically written on the subject. In such a state 

 of things, the attempts that are made to identify certain 

 strata by the nature of the shells they may contain, should 

 be ventured upon, in most cases, with very great cau- 

 tion. We are fully persuaded that many of those fossil 

 shells termed by conchologists fluviatile, are decidedly 

 marine ; that the nature of others, from ignorance of 

 their animals, can never be understood ; and that a 

 great number, now considered identical with existing 

 genera, belong to groups altogether extinct. Until, 

 therefore, all these suspicious points are cleared up, 

 geologists will derive but very little comparative benefit 

 by our modern systems of conchology, and will be fre- 

 quently led to most erroneous conclusions. The " art," 



