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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 7, 



4 y. The great Ireleth slate quarries were noticed in my former 

 paper. The whole hill, in which these quarries are very largely 

 worked, is thrown into most complicated contortions. But through 

 all these complicated curves the planes of slaty cleavage pass con- 

 tinuously, and almost without any deviation in their strike and dip. 

 I hope to return to the description again, in a paper devoted to the 

 examination of the phaenomena of slaty cleavage. But I subjoin 

 several diagrams to convey some notion of the physical conditions 

 of these most instructive quarries. 



4. Ireleth Slate Quarries. 



Note.— In the above diagrams the arrows below the base line point to the direction of the 

 cleavage planes and those above the section to the bedding. 



Most of the beds show spherical concretions, — sometimes filled 

 with an earthy ferruginous matter like the Derbyshire rotten-stone ; 

 sometimes in the form of septaria, with calcareous veins. In these 

 balls are found a few ill-preserved fossils, such as Encrinite stems, 

 Graptolites, corals, and Orthoceratites. Mr. Salter has identified 

 one Orthoceratite with O. suhflexuosum of Munster. Of Graptolites 

 there are probably two very nearly allied species, — one is G. lu- 

 densis. Among the corals is Favosites alveolaris and a Cyatho- 

 phyllum. 



4 Z. To the description of the coarse upper slates I have little to 

 add to the details before given. Many parts of it can hardly be 

 distinguished from the preceding group. It contains numerous con- 

 cretionary balls, with Graptolites ludensis and corals like those of 

 the preceding sub-group (y). It also contains (though rarely) Car- 

 diola interrupttty as is stated in the published abstract of my former 

 paper. The previous descriptions apply only to the country of 

 Low Furness. To assist in making them understood I here give 

 two sections, — one from the Coniston limestone at the south-west 

 end of Cumberland, thence across the Duddon estuary, and over 

 the hills of Furness to the sea near Ulverston (see diagram 5). 



