244 THE JOURNAL OF GEOLOGY. 



base of the series cojisisting of coarse red sandstones, shales and 

 marls resting on the Old Red Sa?idstone. 



The oil shales of Scotland are confined almost exclusively to 

 the " Calciferous sandstone" strata in the Edinburgh district, 

 and the principal seams occur in West Lothian, where the most 

 important oil works are situated, about twelve miles west of the 

 Scottish metropolis. 



Broadly speaking, Edinburgh is situated on a great anticline, 

 in the center of which there rises a ridge of Silurian and Old 

 Red Sandstone rocks, partly igneous and partly sedimentary, 

 whose general strike is northeast and southwest. The hard vol- 

 canic strata and igneous intrusions in these older rocks have 

 produced most of the pictureque ranges of hills in the vicinity 

 of Edinburgh, and the softer beds in the higher parts of the series 

 dip away, with many complications, from either side of the 

 central axis. To the east of the Pentland ridge the inclination 

 of the beds is very high, and comparatively regular, and conse- 

 quently the whole thickness of the calciferous sandstone series 

 can be traversed in a short time. There is also here a large 

 fault running along the base of the hills which conceals the low- 

 est of the calciferous series of rocks and brings up the old vol- 

 canic beds against the upper parts of the oil-bearing strata, and 

 indeed at one place the dislocation has been so great that the 

 calciferous rocks with their oil shales are almost entirely hidden, 

 and the upper beds of the Old Red Sandstone abut almost 

 directly on the base of the marine limestone series. 



The Carboniferous limestones along this line, with their 

 interbedded coal seams, are inclined for long distances at the 

 same high angle and plunge at places almost vertically down- 

 wards beneath the long and regular trough of Dalkeith Coal 

 Measures, from which they emerge five or six miles farther 

 east at a much lower inclination. 



To the west of the Edinburgh anticlinal the structure of the 

 district is much more complicated. The Calciferous rocks 

 spread out for fifteen or sixteen miles in a tumultuous sea of 

 undulations, basins and folds cut up by multitudes of faults, and 



