60 Mr. H. Holland on the Cheshire Rock-salt Dlstrtd. 



recede from the sea, may perhaps be admitted as another argument 

 in behalf of the opinion. 



The principal objection to the theory undoubtedly is, the non- 

 existence of marine exuvise either in the rock-salt, or in the adjacent 

 strata of clay ; a fact very difficult to connect with the idea of a depo- 

 sition from the waters of the sea. Other objections, though perhaps 

 of less moment, arise from the appearance of the earthy salts in 

 smaller proportion in the rock-salt than in sea water ; from the appa- 

 rently partial deposition of the beds, and from the difficulty of ex- 

 plaining the formation of the figured appearances which occur in the 

 substance of the rock. These circumstances, however, will by no 

 means authorize us to reject the general idea which has been given 

 of the origin of this mineral, strengthened as it is by the situation 

 and appearances observed in the foreign salt mines, where the 

 proofs of marine deposition are still stronger than those presented in 

 the Cheshire district. 



I confess I see no sufficient reason for supposing the action of sub- 

 terraneous or internal heat in the formation of the beds of fossil salt. 

 It appears probable that a deposition of muriate of soda from the 

 confined waters of the sea might have taken place without the inter- 

 vention of this agency, and there are no appearances either in the 

 beds of salt, or in the clays accompanying them, which render it 

 necessary to have recourse to the supposition in question. It must be 

 acknowledged, however, that it is difficult to give a satisfactory account 

 of the consolidation of the beds of salt ; nor do I know any opinion 

 on this subject, which can be considered altogether free from objection. 

 A more enlarged discussion of these theoretical points may be found 

 in the Appendix to the Report of Cheshire, before alluded to. 



In dwelling thus minutely upon the natural history of the 

 Cheshire rock-sah district, I am not aware that I have gone further 



