Reports and Proceedings—Geological Society of London. 41 
Beds. The Northumberland succession, together with the Lower 
Carboniferous rocks north of the Tweed, occupies the northern ex- 
tremity of the Pennine Province of the Carboniferous Limestone Series, 
which stretches from Staffordshire 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 semicircle round the igneous massif, nearest to which 
consequently lie the lowest beds. 
The Bernician is mainly built up of sandstones and shales, but inter- 
calated among the arenaceous and argillaceous deposits are the various 
beds of limestone and numerous seams of coal. 
In the Upper Bernician, the limestones are fairly thick, are constant, 
and are truly marine. The calcareous beds of Lower Bernician age 
are thin and impure, and frequently contain St:gmaria and other 
plant-remains. There are a few good marine limestones, but these 
are of local occurrence. 
The Upper Bernician, taking the Redesdale Ironstone Shale as the 
base, answers to Tate’s Calcareous Group; while the Lower Bernician 
is equivalent to Tate’s Carbonaceous Group. 
It is with the Upper Bernician only that the present paper {is 
concerned. 
The whole of the Upper Bernician Limestones belong to the 
Dibunophylium-zone, but they are capable of the following palzonto- 
logical subdivisions :-— 
a = Redesdale Ironstone Shale. 
Shallow-water fauna, mainly lamellibranchs ; corals rare. 
Dibunophyliun near 6 has been found. 
I = Redesdale Limestone. 
D 1 fauna. 
Dibunophyllum @. 
Carcinophyllum @ especially characteristic. 
II = Fourlaws and Oxford Limestones. 
D 2. 
Lonsdalia floriformis enters. 
III = Kelwell, Acre, and Four Fathom Limestones. 
D 2-3 presents in its main character a Zaphrentid phase. 
IVa = Great and Little Limestones. | 
2 
Oe 
Dibunophylhun muirheadi. 
Koninckophyilum magnificum. 
Diphyphyllum dianthoides. 
IVd = Corbridge, Thornbrough, and Robsheugh Limestones. 
The tendency in the Dibunophyllids towards Aspidophylloidal structure 
reaches its highest development. 
1Ve = Fell Top Limestone. 
Characterized by the presence of Dibunophyllum muirheadi mut., cf. 
Dibunophylium y, and Phillipsastrea radiata. 
3. ‘Notes on the Dyke at Crookdene (Northumberland), and its 
Relations to the Collywell, Morpeth, and Tynemouth Dykes.” By 
Miss M. K. Heslop, M.Sc., and Dr. J. A. Smythe. (Communicated 
by Professor G. A. Lebour, M.A., D.Sc., F.G.S.) 
The dyke at Crookdene is exposed in the bed and banks of the 
