Yol. 54.] THE GRAPTOLITE-FATJNA OF THE SKIDDAW SLATES. 463 



32. Tlie Geaptolite-Fauna of the Skibdaw Slates. By Miss G. L. 

 Elles, jN'ewnham College, Cambridge. (Communicated by 

 J. E. Mark, Esq., M.A., E.E,.S., E.G.S. Eead May 4fch, 1898.) 



[Plate XXYII.] 



Contents. 



Page 

 I. Introduction 463 



II. Previous Literature on the Skiddaw Slates 464 



(a) Stratigrapbical. {h) PalEeontological. 



III. Description of Genera and Species 469 



IV. Comparison of the Skiddaw Slate Fauna with similar Faunas in 



Sweden and Canada 525 



V. General Conclusions 525 



{a) Stratigrapbical. (h) Phylogenetic. 



I. Inteoduction. 



The term Skiddaw Slates is tbe name given to all tbe sedi- 

 mentary and contemporaneous volcanic deposits of the Lake District 

 and its neighbourhood, which lie below the Borrowdale Yolcanic 

 Series. Mr. Marr has shown (Geol. Mag. 1894, p. 122) that the 

 main outcrop of these beds lies north of the mass of volcanic rocks 

 which constitute the central hills of Cumbria. This outcrop seems 

 to be continued in a south-south-easterly direction across the eastern 

 end of Ulleswater to Shap, though it is partly covered by a deposit 

 of Carboniferous Conglomerate. 



Another mass of Skiddaw Slate forms the hill of Black Cone in 

 the south of Cumberland, and a small outcrop also occurs near 

 Dalton-in-Eurness.* The same rocks appear to be extensively 

 developed in the Isle of Man, though the beds there seem to be 

 unfossiliferous. 



East of the Lake District the Skiddaw Slates are again found 

 in the Cross Fell Inlier, and have been mapped in the small inlier 

 of Teesdale. 



The beds are always much contorted and faulted, and greatly 

 affected by cleavage ; also in certain places they have been exten- 

 sively altered by the protrusion of igneous rocks through them. 



The largest collections of fossils have been made in the Keswick 

 district, where the beds have been well worked by local observers. 

 Some of these are well preserved, but the best fossils, as a whole, 

 come from the Cross Fell Inlier. The following are the chief 

 localities from which fossils have been obtained : — 



(1) Keswick District. Eandal Crag, Oarlside Edge, and White House 



Fell (Skiddaw), Barf, Outerside, Bassenthwaite 

 Common, Saddleback, Glenderamakin Valley, 

 Troutbeck. 



(2) TJlleswateu District. Aik Beck, Pooley = Eggbeck. 



(3) SiiAP District. Thoruship Beck. 



(4) Cross Fell District. Ellergill, Milburn. 



Q. J. G. S. No. 215. 2 k: 



