CARBONIFEROUS CONODONTS OF \YEST OF SCOTLAND. 339 



presents as smooth, polished, and lustrous an appearance as if they 

 had been derived from some existing animal, and no one would 

 suppose from their appearance that they dated from the long-past 

 ages of the Carboniferous epoch. In some examples the minute 

 denticles are more or less fractured, but this might readily happen 

 even in recent objects of similar delicate structure [the frac- 

 turing is in most cases evidently recent], but in other specimens 

 the teeth are as sharply pointed and their lateral edges as acute 

 as if they had but recently been fulfilling their functions. They 

 excel in their state of preservation those occurring in the Ameri- 

 can rocks, which are for the most part imbedded in shale or lime- 

 stone, and but seldom met with free from the matrix, whereas 

 these Scotch examples are perfectly free from matrix, and thus 

 allow their forms to be much better determined. In composition 

 and structure they appear to be identical with the American and 

 Russian forms, and present a light-brown, translucent, horny 

 aspect. One or two specimens are white and opaque, a difference 

 owing probably to chemical change from exposure. There is 

 equally as great a variety in the form of these Scotch Conodonts 

 as in those from America and Russia, and, while many examples 

 are identical with specimens which are common to these widely 

 separated localities, there are other specimens which vary in 

 detail from any which have yet been figured. Those latter I have 

 indicated below by new names, though I by no means wish to 

 assert that they are to be regarded as distinct species. Our 

 present ignorance of the character of the animals to which these 

 teeth belonged makes it a matter of conjecture as to the value to 

 be attached to differences in their form ; and the discovery which 

 I made of numerous different forms of small teeth and plates 

 associated together, so as to lead to the belief that they belonged 

 to a single individual, renders it highly probable that, notwith- 

 standing the great variety of form of these minute bodies, they 

 may represent but a few species. In the meanwhile, however, it 



very desira^ble to ascertain and figure these different varieties, 

 and until some happy discovery shall enlighten us respecting 

 their relations to each other it will be convenient to give to each 

 of them a distinctive appellation. 



Ko fresh discovery either of fossil or recent forms of life has 

 been made which would tend to clear up the doubts whether the 



