in the Cannd Coal of Fife shire. SI 3 



and that same compressing force. The numerous alternations 

 observed in the coal-measures, and the frequent intercalation of 

 beds of limestone abounding in marine remains, indicate not only 

 frequent changes in the nature of the materials brought from 

 the land, but the predominance of sea over fresh water for long 

 periods, over the areas occupied by the accumulations of trans- 

 ported detritus, and repeated submergence and re-elevation of 

 the bed of the estuary. 



Now, after an examination of the spot and the specimens, and 

 after a careful perusal of Dr Hibbert's memoir, I cannot find 

 any thing in the limestone of Burdiehouse adverse to the theory 

 of its having been so deposited in an estuary; but, on the con- 

 trary, the evidence appears to me strongly to favour that hypothe- 

 sis, and to be hostile to the idea of its being a lacustrine deposit. 



Dr Hibbert himself, in speaking of the great coal-formations 

 of the Scottish Lowlands generally (p. 258), while he makes an 

 exception in regard to this particular bed of limestone, admits, 

 " that even large tracts of dry land might have subsisted, and 

 have been invaded by arms of the sea or estuaries ;" and, in an- 

 other place, in the summary of the evidence he adduces in fa- 

 vour of his theory of a lacustrine deposit, he says (p. 9.Q5), " the 

 calcareous deposite must have taken place in a depression or ba- 

 sin, perfectly surrounded with a dense vegetation, which has 

 been washed into inland waters. But this circumstance, he goes 

 on to say, " would of itself prove little, as we may easily sup- 

 pose that an estuary or arm of the sea might have stretched 

 through a tract where a dense vegetation has prevailed.*" In 

 his account of what he considers an analogous formation in Lin- 

 lithgowshire, Dr Hibbert says (p. ^5)^ " Near Bathgate, a 

 limestone of marine origin may, at its junction with a fluviatile 

 bed, be found to actually graduate into a fresh- water deposit.*" 

 Now, this is exactly such a kind of formation as one might ex- 

 pect would take place in an estuary, where any of the beds 

 might partake, in some degree, of a fresh-water character. 



The evidence which Dr Hibbert considers as conclusive in 

 favour of this limestone being of lacustrine origin is, (p. 264), 



L The absence of all mollusca and conch ifera, of acknow- 

 ledged marine origin. 



