274 Dr Hibbert on the Limestone of Burdiehouse 



NOTES TO SECTION XI. 



Having at length carefully drawn every close and tedious distinction of which I 

 conceived a fresh- water question of this kind was susceptible, — more, in fact, to com- 

 bat the objections with which I have been assailed, than to aid in my own convic- 

 tion, — a perfect weariness of fresh- water deposits, and of ancient lakes or rivers, has 

 more than once tempted me to exclaim, in too literal a strain, with the Mantuan poet, 

 Claudite jam rivos, pueri : sat prata biberunt. 



But this long discussion, in which I have embarked relative to the fresh-water 

 origin of the limestone of Burdiehouse, has not been uncalled for. I have been de- 

 sirous that my memoir should embrace the confutation of every charge upon which 

 I have been attacked. I am unwilling to allude to any particular attack, but as si- 

 lence has but too often been interpreted as an admission of defeat, I must impose 

 upon myself the very annoying task of noticing a few animadversions. 



The first objection strongly urged against me was that the limestone of Burdie- 

 house had not a fresh-water but a marine origin. 



With regard to this counter opinion, — after the numerous facts which I have 

 brought to bear against it, — I will not again combat the objection, that the deposit of 

 Burdiehouse was less under the dominion of the Naiads than of Neptune ; nor will I 

 disturb the opinion publicly expressed against me by the President of the Edinburgh 

 Wernerian Society, for whose old Neptunian predilections I can make every allowance. 



In the second place, my account of a lacustrine limestone existing among the car- 

 boniferous group of rocks was arraigned on the score of originality. 



In order that the force of this charge may be properly estimated, some previous 

 explanation may be necessary. 



Various thin seams, named bands of fresh-water limestone, are common through- 

 out the whole of the coal-fields of Scotland, and scarcely need be enumerated. Manv 

 of them contain fresh- water Unios. Seams of this kind I have observed near Old 

 Cumnock, and other places. 



These bands of limestone cannot fail to be familiar to every geologist who has 

 studied coal-measures. From their having come within my notice, I conceived, as 

 well from this as from other analogies to which I have already alluded, that the 

 existence of considerable beds of fresh-water limestones, to which the name of bands 

 could not apply, was a rational expectation. That my expectation has not been 

 disappointed, the present researches have, I trust, satisfactorily proved. 



In reference to one of these bands of limestone, the originality of my discovery 

 has been arraigned upon the strength of a passage, which appears in the Proceedings 

 of the Geological Society of London, by Mr Murchison, incidental to an account of 

 the coal-fields in the neighbourhood of Shrewsbury. It is stated, that " three thin 

 beds of coal are for the most part observable, and the deposit is distinguished by 



