in Flints of the Chalk. 195 



These two specimens were exhibited to Prof. Ehrenberg 

 during his visit in London, to whom, as to other observers, 

 they were previously unknown. That they should so long 

 have escaped our notice is to me a marvel, and I can only ac- 

 count for it, by making what I feel to be the very extravagant 

 supposition, that the flints hitherto examined did not contain 

 them. They are not like the infusoria, requiring great ampli- 

 fication to be rendered visible at all, but possess, in many cases, 

 all the brightness, and more than half the magnitude, of a silver 

 penny ; and I am even tempted to ask how our geological 

 sportsmen can have overlooked them ; for of the only half 

 dozen gun-flints which have ever been in my possession, I 

 find a brilliant scale sparkling upon the surface of one of 

 them. However, it is now a matter of certainty that we shall 

 all find them, and in great numbers. 



The value of this discovery in a geological point of view 

 cannot be better stated than in the following extract from 

 Prof. Phillips's 'Treatise on Geology^*: " M. Agassiz has 

 proved the importance of the indications afforded by the na- 

 ture of the dermal covering, and applied it to the classification 

 of fishes with peculiar success. Instead of the divisions usu- 

 ally adopted from the nature of the skeleton, — cartilaginous 

 and osseous fishes, — he distinguishes four great orders of 

 fishes from the nature of their scales, and finds that with these 

 differences of scales other great and important distinctions 

 harmonize ; but that the possession of a bony or cartilaginous 

 skeleton is a question of comparative unimportance. The 

 abundance and perfection of scales of fishes in a fossil state 

 render this view, valuable as it is in recent zoology, absolutely 

 essential to a study of the fossil kingdom ; for thus a few 

 scales remaining, may lead to a knowledge of the species or ge^ 

 nera belonging to each epoch, and as portions of fishes are 

 found in every one system of strata, from the ancient silurian 

 to the most recent of lacustrine deposits, we are presented 

 with a second scale of organization nearly as complete and as 

 distinctly related to time, higher in the ranks of creation, and 

 therefore more sensibly dependent on physical conditions than 



* Cabinet Cyclopaedia. Phillips on Geology, p. 88. 

 o2 



