J. E. Marr — The Shiddaw' iSlafes. 123 



glomerate near Ulleswater) with that of the Skiddaw Slates, ranging 

 in a N.N.W — S.S.E. direction, from the east side of Saddleback to the 

 neighbourhood of Shap, across the eastern extremity of Ulleswater. 

 Another mass of Skiddaw Slate forms the prominent hill of Black 

 Comb at the southern end of Cumberland, and a subsidiary outcrop 

 occurs near Dalton-in-Furness. A large part of the Isle of Man is 

 also occupied by Skiddaw Slates. To the east of the Lake District 

 beds referred to these slates are found in the Cross Fell Inlier, and 

 are mapped by the Geological Surveyors in the small inlier of 

 Teesdale ; and it has been suggested by Mr. Aveline that a portion of 

 the green slates of Ingleton is referable to this group. 



The general characters of the Skiddaw Slates have been frequently 

 described. Almost every variety of arenaceous and argillaceous 

 deposit may be found, besides volcanic ashes and lavas. They are 

 distinguished by a general absence of calcareous matter. The 

 Graptolites, which it is the object of the writer to consider more 

 particularly, are generally found in, though by no means universally 

 confined to, the black or blue-grey argillaceous members of the 

 group. These Graptolitiferous argillaceous rocks may be frequently 

 traced in bands running parallel with the general strike of the 

 rocks, and extending for a greater or less distance in this direction. 

 They have been largely worked by local observers, especially by the 

 late Mr. Kinsey Dover and Mr. Postlethwaite in the neighbourhood 

 of Keswick, the result being that our richest collections have been 

 gathered from the vicinity of that town ; and many localities away 

 from it, which are rendered classical by the work of the earlier 

 exponents of the palgeontology of the Skiddaw Slates, — Salter, 

 Harkness, Nicholson, and others, still require much examination 

 before their faunas can be considered thoroughly known. 



The following list of Graptolites, compiled from the Woodwardian 

 Collection, the writings of various authors, notably Nicholson, and, 

 after brief examination of the collection of Mr. Postlethwaite and 

 that in the Keswick Museum, will be sufficient to allow us to draw 

 important conclusions : — 



List of Graptolites from the Skiddaw Slates. 



Didymograptus affinis, Nich. Barf ; Carlside Edge ; Eggbeck ; Ellergill. 



,, hifidus, Hall. Outerside ; E. of Dodd Wood, Keswick; Doddick 



Fell, Saddleback ; Eggbeck ; Ellergill. 

 ,, indentus var. nanus, Lapw. Outerside; Barf; Gategill, Saddleback; 



Glenderamakin Valley, Mimgrisdale ; Thornsliip Beck. 

 ,, Marchisoni, Boeck. Outerside ; Thornship Beck ; Cross Fell area. 



,, fasciculattis, 'Nich. Eggbeck; Thornship Beck ; Ellergill. 



,, gibberulus, Nich. Eandal Crag ; White Horse, N.W. of Skiddaw. 



,, Nicholsoni,'La.-^^. Outerside; Barf; Carlside; Thornship Beck. 



,, nitidiis, BsXl. Barf; Eandal Crag ; Knott Head, Whinlatter Pass ; 



Brundelhow Lead Mine. 

 ,, patulus, KaW. Outerside; Eandal Crag; Eggbeck. 



,, V. fractus, Salt. Barf; Dodd, Brackenthwaite ; New Brow Quarry, 



Upper Lorton. 

 ,, \. fractus, var. volucer, H. 0. Nich. Outerside. 



,, extensus. Hall. Outerside; Eandal Crag; Knockmurton, near 



Lamplugh Cross. 



