Vol. XXviii.] PALAEONTOLOGY OF LANCASHIKE COAL MEASURES. 407 



So far, there is nothing in the fossils themselves which can 

 be indicative of purely marine conditions. 



This is seen to be hardly the case, however, when we 

 consider the forms found in the beds above the Lower Foot 

 Mine. Here the species have increased to eight, three of 

 which are fishes. The occurrence of the latter point clearly 

 to the incoming of a marine phase, which did not advance^ 

 very far, judging by the fact that two of the forms are 

 recorded from one locality each and the other from 

 two. 



The evidence of a marine phase is suddenly emphasised by 

 the shales over the Gannister or Lower Mountain coal, from 

 which no less than 30 species have been obtained. 



Five of these are cephalopoda and eight fishes. The 

 cephalopoda appear here for the first time, and are accom- 

 panied by twelve species of moUusca as contrasted with but 

 two species in the shales below the Gannister. 



The presence of the cephalopoda alone sufiiciently stamps 

 this horizon as of marine origin, and as they are accom- 

 panied by five species of Carbonicola, as against three over 

 the Bassey mine, and two over the Lower Foot, we can 

 reasonably assume that marine conditions were more favour- 

 able for the development of the latter genus than brackish 

 or littoral. 



From what has been written elsewhere it will be under- 

 stood that the horizons above the Bullion and Mountain Four 

 Feet mines are practically one, and it is on this joint horizon 

 that life was most abundant both in species and numbers. 

 Thirty-five species are known to occur, of which twenty- 

 eight belong to the groups Pelecypoda, Cephalopoda, and 

 Pisces. 



The horizon above these two seams is one of considerable 

 importance on account of its wide geographical range. 



