^50 MINERALOGY OF THE REDHEAB. 



ing upwards of a hundred yards, are included 

 on ali sides by the regular strata, observing the 

 general dip and direction, except on the western 

 side, w^here the direction changes from W. by S. 

 to W. S. W. The regular strata at the north 

 side of this interruption, are much intersected by 

 veins of limespar*. Can we account for this ap- 

 pearance, otherwise than by supposing, that a par- 

 tial change in the direction of the depositing fluid 

 occasioned this limited irregularity ; a disturbing 

 force acting laterally or from below, must have 

 changed at the same time the position of the ac- 

 companying beds. Such irregularities in the stra- 

 tification, ought to be studied with care, as they 

 yield instruction to the miner, and afford the geo- 

 logist a touchstone by which to try the truth of 

 his theory. 



To the south of the harbour of Aberbrothicl, 

 the strata of sandstone are from one to three feet 

 in thickness^ split into thin laminae, and the par- 

 ticles cohere very feebly. When pieces of this 

 rock are first raised from the bed, they can be 

 cut into slices with a knife, or crumbled to pow- 

 der by the fingers ; but after they have been ex- 



* I have here used the term calcareous-spar, because sanc- 

 tioned by use and high authority. Perhaps the name lime" 

 spar, a compound of two English words, would be more appro- 

 priate, and preserve a greater uniformity in mineralogical no- 

 menclature. 



