Liberton Old Red Sandstone Conglomerate Bed. 255 



Grange House, a quarry has recently been opened, in which 

 a conglomerate, precisely similar in mineral composition to 

 that of Liberton Brae, is disclosed. The bed has been 

 opened at its outcrop with the surface ; and this may be 

 traced as an elevated ridge, running nearly in the direction 

 of Professor Syme s villa on the one hand, and Marchbank 

 on the other. The dip of the exposed beds, about 25°, is 

 N.E., similar to that of the Grange Quarry. The mineral - 

 ogical character of the bed varies very much even in the 

 small space exposed. For while the conglomerate structure 

 is manifest in that part in proximity to Grange House, the 

 exposed beds in the Morningside direction exhibit the ap- 

 pearance of a coarse-grained sandstone, with here and there 

 a pebble interspersed, — in short, very much the structural 

 appearance presented by the lower beds of the old Grange 

 Quarry, situated a short distance above this new one. The 

 exposed beds we are describing are generally very fissile ; 

 several vertical dislocations are exhibited ; they are five feet 

 in depth, being bounded below by a seam of brownish yellow 

 clay, very similar to that exhibited beneath the greenstone of 

 Salisbury Crags. The direction of this bed, which is generally 

 synchronous with the rest of the Lower Carboniferous series 

 surrounding the city, and its position being considerably be- 

 yond the supposed fault, skirting the valley of the Braids, 

 throws great doubt on the stratigraphical importance as- 

 signed to the Liberton conglomerate. Both beds evidence 

 a rapid current, carrying with it debris from the outlying 

 flanks of the Braids and the Pentlands ; but that they are 

 the passage-beds of one great life system into another, has 

 by no means been proved. The method of seeking the 

 classification of the English carboniferous beds in the Scot- 

 tish system, neglecting the physical proofs whether such 

 beds really exist, has done much to involve in confusion the 

 physical geography of Britain during the Coal era. The 

 appearance of the Liberton bed at the Grange may be chro- 

 nicled, then, as one more fact tending towards the conclu- 

 sions of that increasing class of geologists who hold that the 

 Scottish and Irish carboniferous beds are not on the same 

 geological horizon with those of England, but belong to an 



