29 



Trap Rocks. — These are rare in the district ; Professor Sedgwick 

 has laid down some masses of igneous rocks at Shap Fells, on the 

 south side of the high road ; one of them consists of red felspar with 

 some mica, quartz, and hornblende. The slate rocks are much disturbed 

 in the neighbourhood, and the faults have broken up the cleavage 

 planes as well as the bedding of the rocks, from which Mr. Sharpe 

 infers that the trap is more modern than the eruption of the Shap gra- 

 nite, which took place before the cleaving of the slates, as the cleavage 

 planes run through all the faults connected with that eruption. 



At Biglands, south of Newby Bridge, there is a trap dyke running 

 north-east, which has also disturbed the parallelism of the cleavage, 

 and must be considered as of a modern date : it is not well exposed 

 on the surface, 



The author concludes by a comparison of all the beds with those 

 described by Mr. Murchison in the border counties of Wales, and 

 adopted as the types of the Silurian system, and with those of Den- 

 bighshire and Merionethshire, to which his attention was directed by 

 Mr. Bowman's papers on Llangollen ; he points out the closest re- 

 semblance between the Silurian formation in North Wales and in 

 Westmoreland, while in mineral character they differ most mate- 

 rially from those of Siluria : nevertheless the principal divisions of 

 the Silurian system laid down by Mr. Murchison can be traced in 

 each district by the evidence of the organic remains. 



" On the Stratified Rocks of Berwickshire and their imbedded 

 Organic Remains." By Mr. William Stevenson, of Dunse. Com- 

 municated by the President. 



In this memoir the author gives an account of the characteristic 

 features, the order of succession, and the nature of the organic re- 

 mains of the stratified rocks of Berwickshire. The lowest of these 

 are greywacke and greywacke slate, forming an extensive system of 

 arenaceous and argillaceous strata of various colours, gray predo- 

 minating, found almost everywhere among the Lammermuirs, of 

 which chain they constitute the fundamental rock. In the rocks of 

 this system no undoubted organic remains have been found, but 

 some curious markings occur on slabs, for which it is difficult to ac- 

 count without supposing the influence of organic agency. The grey- 

 wacke presents the uniform appearance of a deep sea deposit, per- 

 haps laid down upon the bottom of a wide-spreading ocean of great 

 profundity, and therefore removed from the disturbing action of 

 wind and tides. The thickness of these strata, as displayed among 

 the Lammermuirs, is very great, but the series is far from being com- 

 plete, there being no appearance of the older strata on the one hand, 

 and on the other their junction with the newer formations is always 

 unconformable. The materials of which they are composed were pro- 

 bably derived from the disintegration of the granites and primary 

 schists to the westward. 



2. The formation next in order is the upper division of the old 

 red sandstone, the members of which rest unconformably upon the 

 upturned ends of the greywacke. The lowest member of it is an 



