282 GENERAL COMPARISON OF 



GENERAL COMPARISON OF THE SCHISTOSE ISLES/ 



IN proceeding to the general examination of the con- 

 nexions and relations of these islands, it must be remem- 

 bered that they were classed in three subordinate groups, 

 the Slate, the Quartz, and the Chlorite isles. On the 

 subject of the first group nothing remains to be added 

 except a few remarks on the beds of chlorite schist, which 

 will find their place in describing the last subdivision ; 

 the relation of each individual to the whole being easily 

 collected from the preceding descriptions. The internal 

 relations of the several members of the second have been 

 also sufficiently detailed. But the limited extent and 

 small number of the islands included in the last sub- 

 division, rendered it impossible to give an account of the 

 series of strata to which they belong, as ample as its 

 importance merits; while the history of these rocks could 

 not be understood without reference to the mainland, 

 where they occupy an extensive tract of country. The 

 following sketch of the general extent, position, and pre- 

 vailing features of the whole district, will render intel- 

 ligible that which must have appeared obscure in the 

 history of these spots ; and from it may be supplied those 

 minor details which were purposely omitted, as being, in 

 their detached state, unsatisfactory. It will, from that, be 

 seen, that the islands of the chlorite division all consist 

 of the prolongations of the beds on the mainland ; the 

 variations of character and position in the strata of the 

 several individuals, corresponding exactly with those of 

 the continental strata from which they are prolonged. 

 This series must be distinguished by the name of the 



* See the general Map, and consult Arrowsmifh'i Map. 



