SANDSTONE OF THE WESTERN COAST. 103 



gneiss. The conglomerate with which it commences, 

 proves that the latter rock has been covered during a 

 certain period of repose by fragments of its own sub- 

 stance ; while the very construction of the sandstone also 

 shows that it is the produce of materials which have been 

 furnished by rocks previously existing. The magnitude of 

 this deposit marks to a certain degree the interval of time 

 which must have passed between the two, and proves, 

 that even among the primary rocks, there have been long 

 intervals of time, attended by changes and revolutions, 

 and productive of depositions of rock, analogous to those 

 which occur between the primary and secondary divisions. 

 In its essential characters this sandstone, where uncon- 

 formable, may therefore be considered a kind of secondary 

 rock, when compared to the primary with which it is 

 immediately connected. 



It may still be questioned, by those to whom 

 these facts are new, whether the unconformable and 

 the alternating sandstone are the same, or whether 

 the former is not actually a secondary sandstone? I can 

 add nothing to the statements on this subject already 

 given. The facts are open to examination, and perhaps 

 they may still require it. To introduce confusion where 

 order was supposed to exist, is no less painful to him who 

 describes than to him who reads ; yet the transition from 

 one species of order to another must pass through confu- 

 sion. The history of chemistry is not the only proof of 

 this truth. Though the preceding views should be incor- 

 rect, though the sandstone of Sutherland should be proved 

 secondary, still this investigation and these doubts will 

 have their use, by extending the history of the secondary 

 strata, and by establishing the existence of circumstances 

 at variance with the predominant characters of their 

 lowest member. It is not difficult to see that, in such 

 an event, important modifications would also be wanted 

 in the characters of the secondary division ; and that 

 the anomalies thus generated will not be less troublesome 



