THE SCHISTOSE ISLES. 303 



consistent. These connexions must be determined partly 

 by their relative positions on the general line of bearing, 

 and partly by their resemblance in certain peculiarities 

 of structure and connexion ; that which is deficient in 

 the one species of proof being compensated by the other. 



It has been shown that in the Garveloch isles, a lime- 

 stone accompanied by a breccia of peculiar character is 

 found immediately following a peculiar schist distin- 

 guished by containing fragments of granite and quartz 

 rock. The same beds, in the same order, although less 

 conspicuously detailed, have been also shown to occur 

 in Isla near Portaskeg ; that which might appear dubious 

 respecting them here, being rendered clear by their 

 perfect exposure in the islands above mentioned. It 

 has also been proved that if the line of direction of 

 either of these is prolonged to the other, it will be 

 found sufficiently conformable to the general bearings 

 already described, to confirm the opinion derived from 

 their resemblance, namely, that they are portions of 

 the same, or of corresponding strata, of which the 

 intermediate parts are either deficient or concealed be- 

 neath the sea. 



In the same way it has been attempted to establish 

 a similar connexion between Lismore and Isla, far 

 removed as they are in position. Notwithstanding that 

 interval, the perfect resemblance of the limestone of 

 the former to that which occupies the middle district 

 of the latter island, together with the conformity of 

 their mutual bearings, seem to point to a similar con- 

 nexion. I shall pursue these analogies and connexions 

 no further ; since a comparison of the details of the 

 different islands as already given, will, with the assist- 

 ance of the bearings and references laid down on the 

 general Map, enable every reader to trace them for 

 himself. 



The next general object of inquiry is to determine 

 the uppermost and lowermost of these collective strata, 



