BUFFALO SOCIETY OF NATURAL SCIENCES 133 



tributed in thin layers. The only other recognizable fossil which 

 occurs in the rock is the so-called Dictyocaris ramsayi, which occurs 

 in considerable abundance" (145, 151). If one searches in the litera- 

 ture back to the time when eurypterid remains were first found in 

 the Pentland Hills, one comes upon a description which is in but 

 poor accord with the most recent one, emanating from the Scottish 

 Survey, although bearing out quite well the statement made by 

 Laurie. John Henderson in 1880 read a short account before the 

 Geological Society of Edinburgh of some fossils which he had dis- 

 covered in the Pentland Hills, in the beds in the Gutterford Burn. 

 A few extracts from his paper will serve to give the clearest descrip- 

 tion which I have yet found of the eurypterid-bearing band. "This 

 bed, which is upwards of a foot in thickness, is mostly made up of 

 what I consider to be a mass of vegetable matter, along with an organ- 

 ism which has been described and figured by Mr. Salter .... 

 as a large phyllopod crustacean under the name of Dictyocaris ramsayi 

 . . . . there is in this bed a large amount of vegetable matter, 

 some of the plant remains showing about one-tenth of an inch of carbon 

 on the surface, and these plant remains are so associated with the sup- 

 posed crustacean remains that it is difficult to determine the one from 

 the other. I am now inclined to believe that the Dictyocaris is of 

 vegetable origin. The fact of finding plant remains in such abundance 

 in the Silurian rocks is, as far as I am aware, a new feature, as until 

 lately true plant remains in that formation were considered doubtful. 

 But there can be no mistaking their character and abundance in this 

 bed, which is so thickly charged with carbon that it looks like an 

 impure bed of coal .... the remains of undoubtful crus- 

 taceans of the genera Eurypterus and Stylonurus in a fair state of 

 preservation occur in the same bed with the Dictyocaris and plant 

 remains .... the bed in which these specimens are got 

 must be at least as low as the Wenlock Shale. It lies several hundred 

 feet below the fossiliferous bed in the North Esk above the reservoir, 

 which is of undoubted Wenlock age" (115). 



We do not know precisely the exact relation between the euryp- 

 terid-bearing bands and the beds containing the other fossils, but all 

 available evidence indicates that they are not identical. Considering 

 the decidedly different facies associated with the eurypterids and with 

 the remaining fossils it seems probable that the former are confined 

 to certain bands or lenses, as is often stated. In any case their occur- 

 rence is still capable of easy explanation whether they are actually 



