Mr. H. Holland on the Cheshire Rock-salt District. 55 



as my observations have gone, is perfectly founded in fact. From 

 the mode of working the mines, it is difficult to ascertain the pro- 

 gressive appearance of these figures in a perpendicular plane. It 

 has been stated to me that their form is a pyramidal one, the area 

 enlarging by a determinate ratio of increase as they are traced down- 

 wards ; but several circumstances induce me to consider this state- 

 ment as a very doubtful one, and certainly founded upon insufficient 

 evidence. 



One very important negative fact remains to be mentioned with res- 

 pect to the internal structure of the Cheshire rock-salt, viz. that no or- 

 ganic impressions or remains have ever been met with in any of the 

 beds of the mineral, which have been worked in this district. This fact 

 rests on evidence of a satisfactory kind, and I am not aware of more 

 than a single instance adduced in opposition to it, and that of a very 

 dubious nature. The same remark may be applied to the strata of 

 argillaceous stone between the two beds of rock-salt. The veins of 

 rock-salt intersecting these intermediate strata contain principally 

 the fibrous variety of the fossil. It may be remarked too of these 

 strata, that at their junction with the upper and lower beds of rock- 

 salt, the lines of division are nearly as distinct, as that between the 

 upper bed of rock, and the superincumbent layers of argillaceous 

 stone. 



Comparative View of the Cheshire and Continental Salt Mines, 



The want of sufficient materials with respect to the history of the 

 continental salt-mines prevents me from entering into circumstances 

 of comparison so minutely as I could have wished ; considering 

 such comparison to affiDrd the best foundation for Inquiries into the 

 origin of the fossil-salt. The best, or rather the only memoir on 



