356 MR MILNE ON THE MID-LOTHIAN AND EAST-LOTHIAN COAL-FIELDS. 



the coal-measures, and that there are not in its conglomerates any rocks newer than the greywacke and 

 felspar of the hills, along the sides of which they are deposited. 



I have often been perplexed with the question, from what source the great abundance of iron could 

 have been derived, which colours the sandstones and conglomerates that repose on the Lammermuir 

 Hills. Near Soutra, I discovered that the greywacke rocks with which these strata are in contact, are 

 reticulated with veins of red iron-ore or hematite ; and it is possible that this circumstance may suggest 

 a solution of the question. If the waters, shortly after these hills were raised by the igneous rocks, 

 were saturated near them with sedimentary matter derived from the greywacke rocks, the deposit would 

 have a red colour. In another place, on the south side of the Lammermuirs (near Cowdenknows in 

 Berwickshire), I observed the older rock, — a felspar rock, — also intersected with multitudes of red iron 

 veins, — in close proximity to the red sandstone formation. 



This theory receives some countenance from the fact, that in Lyndale (near Carlops), the old red 

 sandstone strata are not red, but of a brown or dark yellow colour. The trappean claystone on which 

 they there rest, and from the disintegration of whicli they are derived, — contains no iron. The only metal 

 I have found in it is lead. The lead was worked formerly there to a considerable extent. 



3. The Greywacke and Felspathic Rocks are next to be noticed. 



It is a matter of doubt, whether the Lammermuir range has been elevated since the deposition of 

 the coal-strata. Generally speaking, I think they have not ; — though, at particular localities, as near 

 Dunglass in East-Lothian, and near Leadburn Toll, they probably have been elevated. Except at these 

 points, and there may be a few others, — I am inclined to hold, that the stratified rocks along the southern 

 parts of the district possess the slope which they received on their original deposition. 



It is likewise a question attended with difficulty, to determine whether the Pentland Hills were 

 elevated before or after the deposition of the carboniferous strata. The latter opinion is countenanced 

 by three facts, which are at first sight very decisive. One of them is, that these strata, along the south as 

 well as the north flanks of the Pentland Hills, dip rapidly from the hills, at an angle which is never less 

 than 60°, and generally greater. Another fact is, that in many places near and among these hills, the old 

 red sandstone formation is found broken and interrupted, patches of it being found only here and there. 

 Besides all this, there are places where the stratified rocks, near the Pentland Hills, are traversed by 

 dykes of trap, which are undoubtedly offsets from the great mass of igneous matter belonging to these 

 hills. An example of one of the coulees occurs at Heartside, near Carlops, where the new road was 

 lately cut. These are circumstances, clearly indicating elevation subsequent to the deposition of the 

 carboniferous strata. 



On the other hand, we find that the old red sandstone conglomerate along the flanks of the Pent- 

 land Hills, contains fragments of some of the rocks composing these hills, — shewing, therefore, that certain 

 rocks at least forming part of these hills, were in existence, before the old red sandstone conglomerate was 

 formed ; — and of course before the carboniferous strata were deposited. It is important to observe, what 

 the rocks are which exist in the conglomerate, and what are the rocks not found in the conglomerate. I 

 have found abundance of greywacke, and of many varieties of felspar, — but never any specimens of basalt 

 or greenstone, though undoubtedly basalt and greenstone exist among the Pentland Hills. The inference 

 from this is, that the conglomerate had been formed after the elevation of the greywacke and felspathic 

 rocks, but previous to the elevation of the augitic rocks. This inference is confirmed by an examination of 

 several localities near West Linton, where the stratified are seen in contact with the felspathic rocks. 

 Along the banks of the Tyne, the stratified rocks are resting on a yellow-coloured claystone, of igneous 

 origin. At Linton Bridge, they are horizontal ; and, though they acquire a dip approaching to 30° 

 about a mile farther up, they do not present any of the marks of having been elevated since their ()e- 



