592 FAUNAL SUCCESSION OF THE UPPER BERNICIAN 



I take this opportunity of thanking those gentlemen who 

 have so generously aided me in my undertaking. I am 

 especially indebted to Prof. G. A. Lebour and Dr. Vaughan, 

 to Prof, Lebour for his advice and encouragement whilst 

 carrying out the field-work, and to Dr. Vaughan for deter- 

 mining the corals and for other valuable assistance. My 

 thanks are also due to Dr. Wheelton Hind for naming the 

 lamellibranchs, and to several members of H.M. Geological 

 Survey, namely to Dr. Traquair for identifying the fish remains, 

 to Dr. Kitchin and to Mr. R. G. Carruthers. Lastly I must 

 express my great obligation to Mr. John Dunn, formerly of 

 Redesdale, for allowing me access to his valuable collection of 

 Redesdale fossils — the result of many years' careful collecting. 



II. 



THE BERNICIAN SERIES. 

 The Bernician series forms the upper, and by far the larger, 

 division of the Lower Carboniferous sequence of Northumber- 

 land, and covers the greater part of the county. It is 

 divisible into two groups, the upper or Calcareous Division 

 and the lower or Carbonaceous Division. Below the Bernician 

 strata lie the Tuedian beds, including under the term the 

 Fell Sandstone series and the Cementstone group. The 

 Northumberland succession, together with the Lower Carboni- 

 ferous rocks north of the Tweed, occupies the northern 

 extremity of the Carboniferous Limestone tract, which 

 stretches from Lancashire and Yorkshire into Scotland. 



The Carboniferous strata in Northumberland encircle the 

 Cheviots on the south, east, and north, and dip from the 

 volcanic inlier, so that the general strike forms a rough semi- 

 circle round the igneous massif, nearest to which consequently 

 lie the lowest beds. (See map.) In the soutli and east, the 

 strata may be followed as continuous outcrops. In the 

 districts round the volcanic inlier faulting has entirely 

 destroyed the continuity of strike, but in the north it has 

 spread out the scattered and repeated outcrops into belts, 

 which run in the same direction as the general strike. 



