Vol. 6S.] SUCCESSIOX IN THE NORTH-WEST OF ENGLAND. 539 



land which supplied the quartz-pebbles lay to the east of the type- 

 districts. The most likely source of these pebbles would appear to 

 be the quartz-veins of the Skiddaw Slates and other Lower Palseo- 

 zoic rocks, a fragment of which is exposed in Brownber Pike. 



We cannot, therefore, go far wrong in correlating the beds which 

 underlie the Melmerby-Scar Limestone in the Pennine District 

 with the succession from the Thysanophyllum Band to the base of 

 the JVematophyUum-minus Sub-zone in the type-districts. 



The Xeniatopliyllum - minus Sub-zone. — The Melmerby- 

 Scar Limestone, which overlies the basement sandstones and 

 pebble-beds described above, consists for the greater part of rocks 

 belonging to the Lower Dihunopliyllum Sub-zone ; but a small 

 thickness at the base represents the JV. -minus Sub-zone, and the 

 index-fossil, though not abundant here, can usually be found. 

 The beds are exposed on the right bank of Scordale Beck, on 

 Middle Pell, Middle Tongue, and elsewhere along the escarpment. 



The associated fauna is similar to that alread}" described in the 

 neighbourhood of Shap, and calls for no special remark, though the 

 Cyrtina-carhonaria Sub-zone has not been separated in this district. 

 The beds, therefore, correspond closely with the Shap sequence from 

 the Orton Sandstone upwards, and strengthen the view that the 

 lower sandstone at Scordale Beck represents the Orton Sandstone, 



TheBryozoa Band is well developed in this district, and good 

 exposures occur near the col at the northern end of Long Pell, close 

 to the old sheepfold east of the line of fault already mentioned 

 (p. 535) ; indeed, it was in this district that the importance of this 

 baud was first recognized. 



The rock here is composed of a shaly, grey, bituminous lime- 

 stone, containing a rich fauna closely resembling that of the 

 Bryozoa Band on Weather Hill, in the Shap District. 



The IjOv^qy Dihunopliyllum Sub- zone presents no unusual 

 features ; it appears, however, to be somewhat thinner than in the 

 Western Districts. It forms the bulk of the Melmerby-Scar Lime- 

 stone along the Pennine escarpment. The ' spotted ' beds towards 

 the summit of the sub-zone are especially well developed in 

 Great Eundal Beck, behind Dufton Pike. 



The Upper Dihunopliyllum Sub-zone. — The Yoredale 

 Beds are more fully developed here than in the Shap District. 

 The base of the sub-zone is taken at the first sandstone above 

 the Melmerby-Scar Limestone. 



The Lonsdalia Beds are well exposed on the north side of 

 Scordale Beck, in High-Cup Gill, and in Great Eundal Beck. In the 

 first-named beck the base of the sub-zone lies above the Whin Sill, 

 which is there intrusive in the Melmerby-Scar Limestone ; but in 

 High-Cup Gill the Whin Sill has risen in the series, and at High- 

 Cup Nick lies near the base of the Tyne- Bottom Limestone. It is 



