CHLORITE SCHIST. 165 



possible to decide under what head a particular tract 

 should be ranked ; while the cause of this will be 

 apparent, by recollecting that quartz is common to 

 both, and that the boundary between foliated chlorite 

 and mica is evanescent. To make any remarks on the 

 dimensions, forms, and positions, of its beds, as it- 

 occurs in these situations, would only be to repeat the 

 history of micaceous schist. 



The next association in which it occurs, is as an 

 integrant part of a peculiar series, as yet unnoticed by 

 other geologists, which, in the Description of the 

 Western Islands, I have termed the Chlorite series, 

 occupying a considerable uninterrupted space from 

 Canty re northwards ; and succeeding to the micaceous 

 schist by an undefinable gradation. At first, a bed of 

 the chlorite series occurs here and there in the latter 

 rock, till, encreasing in frequency, they become predo- 

 minant ; while the micaceous schist gradually dimi- 

 nishes so as to be no longer perceptible, except on 

 close examination. During the progress of this 

 change, the stratification, w T hich was so confused as 

 to be scarcely distinguishable, becomes gradually so 

 even and regular as to put on the appearance of a 

 series of secondary strata. The deception is much 

 aided by the thinness of the beds, more especially by 

 that of the quartz rock and micaceous schist. This 

 contrast of character is one of the most remarkable 

 features in this series, as distinguished from micaceous 

 schist ; the latter rock being generally confused, and 

 with difficulty distinguishable into strata ; while the 

 former, even in its vicinity, maintains an invariable re- 

 gularity throughout its whole extent. The resemblance 

 to the secondary strata is also much assisted by the 

 perpetual interchange and repetition of the different 

 substances in this series ; each individual being sue- 



