13 



specimen constituting, according to Dawson, the sole representative of 

 this class of trees in the Palaeozoic, implying "the existence in the 

 Devonian Period of trees of a higher grade than any that are known in 

 the Carboniferous system."'"' 



The fossil wood, as It occurs in the limestone, is always 

 much compressed, and its determination is attended with 

 considerable difficulty. Nevertheless the .specimens are 

 interesting as examples of "petrified woods " related to, and 

 in a sense ancestral to, the fossil woods of the Tertiary and 

 Post-tertiai;y forests of the west, which have furnished so 

 many beautiful and often brilliantly colored specimens for 

 our cabinets. 



The Conodont Bed.— This limestone is from two to two 

 and one-half inches thick, and full of fossils, which on the 

 weathered surfaces stand out in relief. The rock is concre- 

 tionary, with thin masses of shale occupying the deeper 

 hollows. In some places masses of bituminous shale lie 

 between it and the overlying Styliolina limestone, while in 

 others again the two are in contact. The rock is more 

 coarsely crystalline than the Styliolina limestone, and is 

 always readily distinguished from the latter. 



The Conodont bed is interesting on account of the 

 numerous fish remains which it contains, these being usually 

 the plates and jaws of Placoderms, the spines of Sharks and 

 more rarely the scales of Ganoids. Most of the remains are 

 fragmentary, though small perfect plates and scales are 

 occasionally found. When weathered in relief they have a 

 highly dissolved appearance. These fish remains are not 

 confined to the Conodont bed, but frequently pass upward 

 into the lower portion of the Styliolina limestone. 



Another characteristic class of fossils in this rock and the 

 one which has given in it's name, is that of the so-called 

 " Couodonts." These are minute jaw-like bodies, black and 

 lustrous, covering the weathered surfaces of the rock in great 



*Loc. cit. 



