464 MISS G. L, ELLES ON THE GEAPTOLITE [Aug. 1 898, 



At Mr. Marr's request I undertook the description of the grapto- 

 lite-fauna of these heds. My intention at first was to confine 

 myself to a description of the specimens in the splendid collection 

 of Skiddaw Slate fossils in the Woodwardian Museum at Cam- 

 bridge, which now includes that made by the late Mr. Kinsey- 

 Dover, of Keswick. I soon found, however, that it would be 

 impossible to do this without repeated reference to specimens else- 

 where, and it therefore seemed best to make the work as compre- 

 hensive as possible, by including a description of all specimens of 

 interest in whatever collections they might be. This I have been 

 enabled to do, owing to the great kindness of the many collectors 

 of Skiddaw Slate fossils. In the following pages therefore, though 

 the Woodwardian Museum Collection forms the main basis of my 

 work, reference will constantly be made to other collections, 

 especially to those of Prof. H. A. Nicholson, Mr. J. Postlethwaite, 

 and the Collection of the Keswick Museum of Local Natural 

 History. 



Tor some time the graptolite-fauna of the Skiddaw Slates has 

 been considered of especial interest, as possessing afiinities with the 

 fauna of the Quebec Group of Canada, though the exact relation- 

 ships have never been worked out. As I hope to be able to show, 

 the fauna is also very closely related to that of the Swedish 

 PhyUograptus-ski&er, though it probably includes also a fauna from 

 beds at a lower and higher horizon. 



In the descriptions of the species, I have not entered into any 

 detail when a species has been already figured and described, unless 

 the Skiddaw Slate forms show some differences from the type. 

 When it has been possible, I have given a full description of the 

 structure of the proximal end, as I believe this to be a point of the 

 greatest importance. In many cases few, if any, structural details 

 can be made out, but in others the specimens are preserved in 

 relief in iron pyrites, and show more detail than has been noticed 

 by the authors who have previously described them. The absence 

 of any remarks concerning structure may be taken to mean that 

 the specimens were not sufiicieutly well preserved for such to be 

 made. 



In a few cases generic descriptions have been modified in accord- 

 ance with the results of recent work, and in some cases also, for 

 similar reasons, a modification has been made in the description 

 of a species, or a fuller description given than that already in 

 existence. 



II. Previous Literature on the Se:ii>daw Slates. 



{a) Stratigraphical. 



1820, 1832. The earliest account of the Skiddaw Slates is that given 

 by Otley in 1820, in the Lonsdale Magazine, vol. i, p. 433, 

 the next being that of Prof. Sedgwick, published in Proc. 



