MUSEUM OF THE NATURAL HISTORY SOCIETY. 273 



Name and Locality. Reference. 



Urocordylus reticulatus,i/«tt.0L4^.,Nat. Hist. Trans., 

 Loc. — Black shale above Low Main Yol. 3, p. 310. 



Seam, Newshani Colliery. 



Batrachiderpeton lineatum, Nat. Hist. Trans., 



Hancock et AttJwy, Yol. 4, p. 208, pi. 4. 

 Loc. — Black shale above Low Main 

 Seam, Newshani Colliery. 



Gannister beds. — These consist of strata of thin-bedded sand- 

 stones and shales, with thin seams of Coal and beds of hard, 

 crystalline, siliceous rock (Gannister.), full of rootlets of a 

 Stigmaria. Yery feebly developed in Northumberland, but 

 becoming thicker in some parts of Durham. Aviculopecten 

 fapyraceus is the most characteristic fossil. 



The fossils of this series are not well known. Stigmaria 

 stellata seems to be peculiar to it, and in the beds of the 

 Gannister series Prof. Lebour has found specimens of Aviculo- 

 pecten papyraceus, a marine bivalve characteristic of this portion 

 of the Carboniferous rocks in Yorkshire and in coal-fields further 

 south. The same fossil has also been obtained from the same 

 series of beds in the south of the county of Durham. Lingula 

 mytiloides of considerable size has been found in shale in the 

 neighbourhood of Ovingham in connection with a small working 

 for Coal. 



Stigmaria stellata, Goepp. Gatt.Poss., pi. 9,f. 12. 



Lingula mytiloides, Sow. Sow.M.C.,t.l9,f. 1,2. 



Aviculopecten papyraceus, Goldf. Pet., t. 116, f. 5. 



Millstone Grit. — In this division is included the series of 

 grits, sandstones, and subordinate shales between the Gannister 

 beds and the uppermost bed of carboniferous limestone, which is 

 locally termed the Pell Top limestone, from its usual position 

 near the top of the fell. It is chiefly composed of sandstones 

 and grits, some of which are very coarse, enclosing large angular 

 pieces of quartz. The beds of this division are of variable thick- 

 ness, being more strongly represented in the South than in the 

 North. 



