Yol. 68.] SUCCESSION IN THE NOETH-WEST OF ENGLAND. 501 



associated with a large Diphyphylloid Litliostrotion resembling the 

 species found at Blackstone Point. The Michelinia is the large 

 form of Miclielinia yrandis characteristic of the base of the zone 

 in the Purness and Grange Districts. A few feet of fossiliferous 

 beds, apparently lying near the summit of the zone, crop out in 

 Tarn Sike: and here Caninia ojlindrica is associated with early 

 specimens of Litliostrotion martini. One specimen of CUsiophyllum 

 midtiseptatum has also been collected from this exposure. The con- 

 <3lusion, therefore, must be drawn, either that Miclielinia did not 

 •enter this district until the end of the period during which the 

 Miclielinia Beds were being deposited at Arnside ; or that the Diphy- 

 phylloid Litliostrotion fauna entered here somewhat earlier than 

 in the Arnside District. The latter view is adopted here, chiefly 

 for convenience in mapping, and these beds are therefore repre- 

 sented in the map and section of the district as belonging to the 

 Michelinia Zone (PI. LIII & PI. LVI, fig. 2). 



The following species have been collected from the exposures 

 mentioned above : — 



Caninia cylindrica (Scouler). i Syringopora geniculata Pbill, 



'CUsiojih/ilum multiseptatura, sp. mov. 



CyathophyUum rnultilamellatiim Chonetes carinata, sp. nov. ; rare. 



M'Coy. Productus hemispheric us Sb}'. 



Biphyphyllum aflf. lateseptatiim Prodiichis corrugato-hemisphcricus 



M'Coy. Vaughan ; early form. 



Liihostrotion martini M.-Edw. , Martinia cf. ovalis (PhilL). 



Lophophyllum sp. I 



Michelinia grandis'M^Coy . i Schizostoma catillus (Phill.). 



The Productus-corrugato-hemispliericus Zone: the J/ 



Oastropod Beds. — As already pointed out, a considerable 

 thickness of calcareous rocks referable to this sub-zone occurs below 

 the Ashfell Sandstone in this district, and passes downwards into 

 the Miclielinia Bed of Keld Sike. The sub-zone includes the whole 

 •of the Ashfell-Sandstone Series, and also probably a few feet of 

 the overlying grey platy limestones, which immediately underlie 

 the Oyrtina-carhonaria Beds of Ashfell Edge. At the western end 

 of the district near Scandal Beck, below Gallows Hill, the highest 

 layers of limestone yield numerous casts of Bellerojylion and masses 

 ■of Alveolites etliericlgi. The Ashfell Sandstone contains two or 

 three calcareous layers, the most interesting of which occurs near 

 the top of the sandstone, and is well exposed in the old quarries 

 {north of the road) a little below the summit of Ashfell Edge. 

 Here several species of corals and brachiopods occur in a good state 

 of preservation. The fossils are quite unsilicified, in marked con- 

 trast with those which occur in the overlying Cyrtina-carhonaria 

 Sub-zone. This calcareous layer is covered by a thin layer of 

 reddish marl, which may have served to protect the fossils from 

 solution or silicification. The fauna is, on the whole, that which 

 is characteristic of the Gastropod Beds elsewhere ; but it includes 

 •also two rolled specimens of Camaroplioria isorliynclia, and a frag- 

 ment of Syringothyris cuspidata, Zaphrentis ennislcilleni enters 

 here at a somewhat higher horizon than at Shap, and in addition 



