CHLORITE SCHIST. 167 



the extreme regularity of the strata, renders the 

 whole very conspicuous, and strongly distinguished 

 from the shapeless and contorted beds of micaceous 

 schist. The various alternating substances., of more 

 rare occurrence and of a subordinate character, will 

 be found in the Classification of Rocks. 



As the next series in which Chlorite schist forms a 

 member, is described under Argillaceous schist, I need 

 here only say, that the predominant substances in it 

 are micaceous schist, clay- slate, and graywacke. It 

 occurs here under numerous aspects ; many of the 

 varieties resembling in structure the accompanying 

 grayvvackes, and differing only in the substitution of 

 scaly chlorite for indurated clay; while it here also 

 presents transitions into clay-slate. And, in the last 

 place, it is found, though rarely, accompanying gneiss : 

 immediately following, and, further, alternating with 

 that rock ; while a gradation between the two also 

 occurs, producing varieties which may be ranked 

 under either, as they tend most to the one or the 

 other. This was already indicated under Gneiss. 



In compliance with the custom of geologists, I have 

 here noticed the metalliferous reputation of the rocks 

 described, though I know not that any useful informa- 

 tion is conveyed by this popular usage. As a question 

 of theory, there is assuredly none ; since we know of 

 no necessary connexion between any rock and the 

 metallic veins which it may contain ; while, in practice, 

 it appears equally fruitless ; since the same rock, in 

 one country, abounds in metallic veins, when, in an- 

 other, it is utterly barren. Whether chlorite schist is 

 to be ranked among metalliferous strata in foreign 

 countries, remains to be known ; as it has been very 

 imperfectly described. But as the barrenness of Scot- 

 land in metals is notorious, their absence from our 



