Geological Society. GS3 



Por purposes of detailed description, the Shap-Eaveiistoiiedale 

 area is taken as the tj-pe, and the other districts are briefly com- 

 pared with it. It is shown that in no one district is a complete 

 development of all the zones observed, and that it is only by 

 taking a broad survey of the whole area that the detailed fauual 

 sequence can be definitely established.' In the Shap area the 

 Miclielhiia-megastoma Zone is scarcely represented, while farther 

 west the fauna of this horizon is one of the richest in the whole of 

 the North-Western Province. 



The changes in the fauna of certain zones, when traced over large 

 areas, often depend more on the lithologieal churacters of the rocks 

 and their modes of deposition than on the introduction of new forms 

 at definite horizons : thus certain corals, such as Zaphrentis ennis- 

 Tcillcni, which is found to be associated with argillaceous deposits, 

 characterize different horizons in different districts. 



The deposits are shown to be for the most part of shallow-water 

 origin. The period of greatest submergence appears to have been 

 during the deposition of the Nematophyllum-minus Beds and the 

 Lower Dihimophyllum Beds. 



The lowest deposits are characterized by highly magnesian 

 limestones; these appear to have been deposited under lagoon- 

 like conditions which encouraged the growth of calcareous algae., 

 especially SoUnopora, and these in many places contribute largely 

 to the formation of the deposits. The majority of the limestones 

 throughout the series are rich in foraminifera, and the more slialy 

 layers in ostracods and bryozoa. 



The silicification of the organisms at many horizons in the 

 sequence is discussed, and the conclusion is arrived at, that both 

 silicification and dolomitization of the limestones were practically 

 contemporaneous with the deposits in which they occur. The 

 presence of spotted and ' brecciated ' limestones is shown to be 

 characteristic of the upper portion of the Lower DihunopJiyllum 

 Zone. 



The movements which have affected the rocks in the Arnside 

 district have been the result of nearly horizontal thrusts, and 

 it is shown by means of zoning that the beds have, in places, 

 been inverted and are dipping at over 120°. 



The palaeontological divisions here described are correlated with 

 their probable equivalents in the Bristol area ; but no exact com- 

 parison has been found possible in the case of the lowest beds, 

 which occur in Pinskey Gill. 



In the paleeontological portion of the paper several new species 

 of corals and one new genus are described, and the aflSnities of 

 several corals and brachiopods are discussed. 



^ Thus the lowest zones are practically absent from the Cross Fell area, since 

 the base of the Melmerby Scar Limestone represents an borizon high up in the 

 Nematophi/llum sub-zone : showing that the complete submergence of this 

 district did not take place until long after that of the area fai-ther to the west. 



