DR. J. E. MARK ON THE LOWER 



[March 19 13, 



Mon ticuliporoids. 



Dicellograptus anceps Nich. 



Turrilepas. 



Trinucleus seticornis (?) . 



Ampyx turaidus Forbes ? 



Tlemopleurides (Caphyra) radians 



Barr. (one specimen). 

 li. (Caphyra) sp. 1 (very abundant). 

 Rernopleurides (sensu stricto) sp. 2 



(two specimens). 



Mlanus. 



Phillipsinella parabola Barr. (fre- 

 quent). 



Lichas. 



Cybele rugosa var. attenuata Reed ? 



Phacops (Dahnannites) robertsi Reed 

 (very common). 



Phacops (Pterygometopus 1) sp. (rare). 



Phacops (Acaste) cf. doumingice 

 Murch. (common). 



The succeeding beds will be spoken of as the Stauroceplialus 

 Beds, although the index-genus has not hitherto been detected 

 below the contemporaneous volcanic rocks which occur near the 

 middle of the division so named. 



A few yards above the mouth of Watley Gill the main beck 

 shows a passage from the Phacops-robertsi Beds into hard, blue, 

 flaggy mudstones which extend up stream to the point where the 

 beck leaves the moorland above to enter the highest part of the 

 enclosed ground up which we have been tracing it. 



On reaching the moorland, we note that calcareous beds become 

 important ; and a thick white limestone, with fragmentary fossils, 

 recalls, as regards lithological characters, the Keisley Limestone. 



I shall speak of the strata from the top of the Phacops-robertsi 

 Beds to the base of the volcanic group as the ' beds below the 

 volcanic group.' They have yielded here : — 



Dicellograptus anceps. 

 Climacograptus normalis Lapw. 

 Glyptograptus persculptus Salt. 

 Tentaculites anglicus Salt. 



Ateleocystites (?). 

 Trinucleus. 

 Illmnus. 

 Orthis. 



Above the beds just described comes the contemporaneous vol- 

 canic group, of which a full description is given by Dr. Strahan in 

 the Geological Survey Memoir. It is associated with fine ashy 

 calcareous shales, which weather olive-green. 



Similar ashy shales weathering green, among which are inter- 

 calated thin calcareous bands, extend above the lavas and coarser 

 volcanic ashes to a point about 200 yards below the junction of 

 the upper tributaries of Backside Beck, namely, Spengill and Stock- 

 less Gill. They are succeeded by grey-blue pencil slates, the normal 

 Ashgill Shales. The beds between the volcanic group and the 

 Ashgill Shales will be spoken of as the ' beds above the volcanic 

 group.' In Backside Beck they have yielded the following fossils : — 



Dicellograptus anceps. 

 Dicellograptus sp. 

 Climacograptus normalis. 

 Orthograptus truncatus var. abbrevi- 



atus Elles & Wood. 

 Mesograptus modestus Lapw. ? 

 Nymplwgraptus ('!) . 

 Retiolitid. 



Agnostus trinodus Salt. 



Trinucleus seticornis (?) . 



Ampyx. ' 



Dindymene hughesice Roberts ? 



Sphcerocoryphe thompsoni Reed. 



Staurocephalus globiceps Portl. ? 



Skenidium. 



Coiiularia. 



Just below the Ashgill Shales, and forming the very top of the 

 beds above the volcanic series, about 10 feet of argillaceous limestone 



