620 FAUNAL SUCCESSION OF THE UPPER BERNICIAN 



Notes : — The Brachiopods comprise no very distinctive 

 forms, but connect the Four Fathom Limestone with the Great 

 Limestone above and the "Acre" below. 



Saccammina carteri forms a band* in the limestone in the 

 south of the county but is rare in the north (cf. the Acre 

 Limestone). 



The rare annelid cases SerpiiUtes carbonarivs are plentiful 

 at Denwick Lane Quarry near Alnwick. 



The overlying shale is usually very fossiliferous. The 

 forms collected in the Cambo Quarry are all from this grey 

 shale. 



The Great Limestone. 



(=The Dryburn Limestone of North Northumberland.) 



From the extreme west this thick bed may be followed across 

 Northumberland almost to the Tweed. Entering the county 

 from Cumberland it runs parallel to the Tyne, never at any 

 great distance from the river, till it approaches Watling Street. 

 At Bewclay it turns northward and continues that course as 

 far as Green Leighton, when it again changes its direction, 

 this time to the north-east. The Great Limestone and the 

 calcareous bed immediately below it are traceable as continuous 

 outcrops onwards from Green Leighton to within half a mile 

 of Lesbury. North of the Aln, faulting destroys the continuity 

 of strike, but the disconnected outcrops with their various dips 

 and strikes form a band, which advancing northwards from 

 Alnwick occupies the coast between Howick Burn and Beadnell. 

 Beyond Beadnell the lower beds (with a few of the middle 

 beds faulted in among them) come into the coastal section. 

 Appearing again on Holy Lsland, this band of Middle 

 Limestones advances inland to Lowick, when faulting once 

 more diverts its course, and after several repetitions the band 

 finally strikes out to sea at Scremerston. 



* I did not see tlie band at Haltwliistle, but it is very prominent at Haydon Bridge, 

 Fourstones and Ryal. 



