Ml'. Tate on the Bencichshire Mountain Lunesto)ie Fauna, lot 



Productal Limestones. Encrinites are locally numerous, and liave 

 given the name of Enerinal Limestones to other beds. 



The Mountain Limestone occupies nearly the whole of that part 

 of Northumberland, M^hich lies northward and westward of a line 

 drawn from the mouth of the Aln to Eiding Mill on the Tyne ; 

 but of this group, only a few of the lower beds are prolonged into 

 Berwickshire, and they cover but a small area. One narrow strip 

 of them extends from the mouth of the Tweed along the coast, for 

 about five miles northward of Berwick. On the north side of the 

 Cambrian or Silurian axis they overlie the Tuedian group, from 

 the Cockburnspath Cove to Dunglas biu-n, the northern extremity 

 of the county ; but the same group of beds is continued into 

 Haddingtonshire. 



4 — The Tuedian Group. In 1856, I applied this name to a 

 series of beds, lying below the Mountain Limestone, which are 

 largely developed on the Tweed. They consist of grey, greenish, 

 and lilac shales, sandstones, slaty sandstones sometimes calca- 

 reous, thin beds of argillaceous limestone and chert, and a few 

 buff magnesian limestones. Stigmaria ficoides, Lej)idodendra, 

 Coniferous trees and other plants occur in some parts of the group ; 

 but there are no workable beds of coal. The Fauna consists 

 chiefly of fish remains, Modiolse and Entomostraca. In one bed 

 on the Tweed, Orthocerata and Pleurotomarise — marine MoUusks 

 — are associated with Coniferous trees. The whole group is es- 

 pecially distinguished by the absence of Brachiopods, which are 

 abundant in the overlying Mountain Limestone. It forms a marked 

 transitional series, intercalated between the Mountain Limestone 

 and the Old Eed Sandstone. Generally fresh-water and lacustrine 

 conditions are indicated ; and when marine remains do occur, they 

 are accompanied with plants which ap'pear to have been swept 

 into a shallow estuary. 



This group occupies a considerable area in the south of Ber- 

 wickshire, and there are good sections on the Tweed and White- 

 adder ; it is exposed on the coast from Burnmouth to near Lammer- 

 ton Shiel ; and it is seen also, on the north side of the Lammermuirs, 

 on the coast between the Pees mouth and Cockburnspath Cove. 

 In Northumberland, there are sections of it in Garmitage bank 

 and Crawley dean, which are from six to nine miles westward of 

 Alnwick ; and the same group is tilted up against the Cheviot 

 Porphyry in Biddleston burn, and in the Coquet below Linn Brig. 



IV. — The Permian formation occurs only in two small patches 

 in Northumberland, at Tynemouth and Cullercoats, where the 

 Magnesian Limestone overlies the Coal Measures. 



The following list is limited to the organisms observed in the 

 narrow strip of Mountain Limestone along the Berwickshire coast ; 

 and in giving localities I use the term Berwick for that part of the 

 coast which is near to the town. 



Class— PISCES. 

 Genus — Holopttchhts. Agassiz. 

 1. H. Sihherti. Ag. 



A tooth in black carbonaceous shale, Lammerton, associated 



