til 



BLACK SLATE. 



This slair is black, and each layci is often slightly glased by a film of carbonaceous 

 matter. Black calcareous layers appear in llie slate only a short distance from the locality 

 of the fossils, l.ut diligent search there has not been rewarded by the acquisition of organic 

 bodies of any kind. The lamina-, which are quite thin, often exhibit intervening spaces 

 of disintegrating red coarser and more friable particles than those (-(imposing the slate, in 

 which \vi- sometimes observe traces of organic matter, too obscure, however, to enable us 

 to form an opinion Of its nature. 



This mass has BO essential character by which it can be distinguished from other slates, 



though (he color ma] serve to re veil perhaps from the greenish laconic slate which 



appears but a short distance to the east. Assuming that its fossils are distinct from the 

 rocks of this and the other systems, and provided the\ wen- as numerous as those of most 

 fossiliferous rocks, there would lie no difficulty in recognizing it. As the matter now stands, 

 we have only three specimens of trilobites, and a fragment of something which appears 

 to be an annelide, but may prove to be a trilobite thai shall form a connecting link between 

 the Crustaceans and Annelides. 



In consequence of the uncertainty in regard to the light in which this mass ought to be 

 viewed, I dismiss the further consideration of it for the present. The character of the 

 trilobites may be seen in the annexed figures. 



Fig. 8. 



Atops trilineatns. 



, is the head of a trilobite, which seems to belong to an intermediate genus between Calymene and Triarthriu 

 The head and part of the body an- well preserved in one specimen; but the other (No. '.!), is unfortunately 

 badly worn. The latter I at first considered the same species ,i~ that represented by No. 1 ; but on farther 

 examination, I have little doubt that they are distinct. The ril.s, of which I can easily count fifteen from 

 the buckler to the posterior extremity of the specimen, arc drawn too coarsely in the figure. The tail is 

 acute, but not prolonged into a spine : there are no markings upon the buckler. The specimen, however, 

 is too imperfect for a name, and would not have been noticed at all but from a wish to illustrate the rock as 

 far as possible by its organic bodies. 

 : , I have named Atop* trilinea.hu. The absence of eyes, however, is not a distinctive mark : the three species 

 are blind. The Atopt is evidently allied to the TriarthrUM Ixrkit, so abundant in the Utica slate ; the Lines 

 in this, however, are direct or transverse to the middle lobe : there is an additional pair in the Atopt 



