654 SERPENTINE. 



modes ; forming large irregular masses, or smaller 

 nodules; or else stratified in a manner more 

 decided and general, or in the shape of small 

 evanescent beds included in other strata. 



In some instances indeed, as in Aberdeen- 

 shire, they form nodules in granite ; a position 

 in which I believe limestone has not been found. 

 It ought also to be added, as a correction to 

 the article on serpentine, that this rock is occa- 

 sionally schistose ; splitting, as it would appear, 

 always in the direction of the stratum. 



In Shetland, serpentine contains chromat of 

 iron; often in great abundance, and so inter- 

 spersed in grains throughout the rock as mate- 

 rially to alter its appearance and characters. 



In consequence of these two alterations, I 

 have thought it necessary to reprint the tabular 

 view of rocks given at p. 78 ; which will there- 

 fore now stand under the following form : 



