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



these, with the exception of a few of the most superficial, appearing 

 in similar progression in each mine. The clays, or argillaceous 

 stone, of which these beds are composed, are indurated in different 

 degrees, tinged with various shades of red, blue, brown, &c. and 

 usually contain a portion of sulphate of lime. They are known 

 to the miners by the general name of metals ; a distinctive appellation 

 being given to each from the shade of colour which it assumes. In 

 the section of strata, annexed to this paper, these appearances are 

 noted with some degree of minuteness ; and that they may more 

 accurately be known, I have sent a few specimens, illustrative parti- 

 cularly of the induration of the clay strata, and of their admixture 

 with the sulphate of lime. It will be observed that, though these 

 clays in general possess a considerable degree of induration, there are 

 some of them sufficiently porous to admit the passage of water 

 through their substance. Where this structure of the clay occurs it 

 goes by the name of the shaggy metal^ and the fresh water which 

 makes its way through the pores has the expressive appellation of 

 Roaring Meg. This term will not appear too strong, w^hen it is 

 mentioned that in the mine from which the section of strata wa8 

 taken, and where the shaggy metal was found at the depth of twenty- 

 six yards, the quantity of water, ascertained to issue from its pores 

 in one minute, was not less than three hundred and sixty gallons ; a 

 circumstance greatly enhancing the difficulties of passing a shaft 

 down to the body of rock-salt. 



A portion of salt, sufficient strongly to affect the taste, is found 

 to exist in many of these beds of argillaceous stone : and this saltness 

 increases ^ as might be expected, as we approach the body of the rock- 

 salt. In the strata or layers immediately above the rock, which in 

 all the mines are perfectly uniform in their appearance and structure, 

 it is particularly remarkable. It may be observed, however, that 



