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V.—On the Geology of Cockburnlaw, and the adjoining District, in Berwickshire ; 
with a Map and Sections. By Witu1am Stevenson, Dunse. 
The portion of Berwickshire, of which the object of this paper is to describe 
the more remarkable geological features, comprises, within a very limited space, 
an assemblage of phenomena of the highest interest, in relation to the wonderful 
changes which this part of our island has undergone in the earlier periods of the 
earth’s history. Its situation is immediately to the north of Dunse, and its area 
is about 16 square miles, within which are comprehended the junctions of the 
greywacke rocks of the Lammermuirs, with the strata of the old red sandstone 
formation, and of the latter with the lower members of the coal measures. The 
chief eminences within the district are Cockburnlaw, which attains a height of 
912 feet above the level of the sea; Dunselaw, 630 feet; the Knock, Borthwick, 
and Castlemains Hills; and the Staneshiel, a hill of the same formation as Cock- 
burnlaw, from which it is separated by a ravine of 300 or 400 feet deep, in which 
the Whiteadder flows. The general topographical features of the district will be 
best understood by reference to the accompanying map. 
In treating of our subject, we propose to describe, 1st, The stratified rocks of the 
district ; and, 2d/y, The igneous rocks, and the changes of structure and position 
which have been effected by their agency upon those of aqueous origin. 
I. STRATIFIED Rocks. 
1. The Greywacke of the Lammermuirs. 
The strata of this important series of deposits (the most ancient of the district 
under consideration) are finely exposed in many localities, consisting of arena- 
ceous and argillaceous beds, of great, but as yet, unascertained thickness, the for- 
mer constituting the greywacke proper, and the latter the greywacke slate. The 
oxides of iron and manganese are widely diffused among these strata. Mag- 
nesia enters pretty largely into their composition; but there seems to be an al- 
most entire absence of calcareous matter, there being no beds of even impure 
limestone interstratified with the greywacke, and but a small quantity diffused 
through its masses. Sulphate of baryta is also very generally met with, in the 
form of veins of various sizes up to a foot or more in width, and occupying fissures 
in the greywacke. Near Elmford, the cleavage fissures of the greywacke strata 
are filled with this mineral. 
No decided traces of organic remains have hitherto been discovered in the grey- 
wacke of this part of the Lammermuirs. On some slabs from a quarry near 
Hoardweel, some curious relieved markings appear, which may prove to be of or- 
VOL. XVI. PART I. I 
