ARRAN. GEOLOGY. SCHIST. 363 



rocks of that island, will hereafter be very apparent. 

 It is here therefore obvious that the argillaceous schist 

 is nearer to the granite than the micaceous; whereas 

 in other places on the skirts of the mountains, that 

 order is reversed. 



About Corry, a coarse graywacke occurs, similar to 

 that which elsewhere accompanies this series, and the 

 same substance will be found in many other places 

 throughout the north-eastern tract ; being, like the 

 former, occasionally nearest to the granite, and pre- 

 senting therefore an anomaly similar to the former; if 

 that may be considered an anomaly which is inconsistent 

 merely with a hypothetical order of succession. In 

 Glen Halimidel, the argillaceous, chloritic, and micaceous 

 schists are so intermixed, that it is impossible to 

 determine which occupies the greatest space near the 

 fundamental rock ; and here slate quarries are wrought 

 both in the chloritic and argillaceous varieties. One 

 of these rocks is remarkable, inasmuch as the base 

 of chlorite schist is found to contain distinct imbedded 

 fragments of common blue clay slate. 



But it is unnecessary to protract these details, as 

 they will necessarily again come under review in the 

 description of Bute. 



Having thus finished the local history of the schistose 

 rocks of Arran, it becomes an object of interest to 

 compare them with those of the adjoining tracts to 

 which their analogy was already pointed out. That 

 which is invisible in this island, from the causes already 

 stated, is abundantly obvious elsewhere ; while that 

 which is here confused, is also elsewhere regular: it 

 remains to ascertain whether a cause can be assigned 

 for the confusion of that which is obscure, by comparison 

 with the regularity of that which is obvious. 



As a full detail of the series of argillaceous schist 

 will unavoidably be required in Bute, where it forms 

 a conspicuous feature, it is only here necessary to say 



