^88 FresJi^ Water Limestones in the Vicinity of Edinhiirglu 



stance, that greenish-coloured beds of trap-tufF of igneous origin, ori- 

 ginally perhaps ejected in the form of. a hot tufaceous mud, are in- 

 terposed among the strata in divers places, one of which has acquired 

 the thickness of nine feet, lead to the irresistible conclusion, that the 

 calcareous beds of Kirkton in their elaboration were in immediate 

 contiguity with some volcanic focus, and that in their original de- 

 velopment they must have exhibited the phenomena of hot springs 

 charged with earthy matters, principally calcareous, such as are fami- 

 liar to the geologist at the present day, in districts where the volcanic 

 agency is still in activity. 



From this fresh-water limestone the author collected several 

 plants, viz. Ferns, &c. of the same kind as are usually found in the 

 carboniferous group of rocks. No remains of fish, as far as he could 

 learn, have yet been detected in the deposit, nor, considering the 

 circumstances under which the limestone was formed, could they 

 perhaps be reasonably expected ; but he is inclined to suspect that 

 relics of some amphibious animal allied to the tortoise have been 

 occasionally discovered. 



The upper strata of this deposit are either alternated with, or sur- 

 mounted by, beds of argillaceous shale, mixed with seams of ironstone. 

 The whole of the strata dip to the west or north by west, and are 

 succeeded, as far as can be learned from the covered state of the 

 ground, by alternating beds of sandstone and shale, which, at the 

 distance of less than half a mile from Kirkton quarry, underlie thick 

 limestone beds containing marine shells and corallines. Lastly, all 

 the beds of this vicinity seem to have been surmounted by masses of 

 feldspar rock, occasionally columnar. 



The inference to be drawn from these observations, is, that the fresh- 

 water deposit of Kirkton, like that of Burdiehouse, has an earlier date 

 of origin than the marine limestone of the district, and that import- 

 ant geological changes, probably of a gradual nature, had contributed 

 to depress the lacustrine deposits which had thus been formed, be- 

 neath the level of some subsequent invading ocean. 



