PICTURESQUE CHARACTERS OF ROCKS. 55 



present this feature, will deceive hiirfself and impede 

 his own progress. He will commit similar errors at 

 every step, if, on the other hand, he shall resolve to 

 consider as granite, every distant hill that is crowned 

 with pinnacles and diversified hy an acute indented 

 outline. No eye can distinguish between the serra- 

 tures of the Arran mountains and those of theCuch- 

 ullin hills, although the former consist of granite and 

 the latter of Hypersthene rock. The gneiss of Harris 

 often presents features exactly similar; nor would 

 any thing short of manual examination convince the 

 observer, that the pinnacles which rise along the spiry 

 ridges of Kea cloch in Rossshire are formed of sand- 

 stone. Even limestone is known to be occasionally 

 disposed in the same manner; and the innumerable 

 spires of Montserrat in Spain are the produce of a 

 conglomerate rock. 



Even in the more minute features, granite cannot al- 

 ways be distinguished from other rocks, although under 

 the very grasp of the observer; *if, confiding in the 

 accuracy of his eye, and relying on his own imagined 

 experience, he shall trust to that alone. In a thousand 

 places in Aberdeenshire, the external forms of the 

 masses, the cairns, and the loose blocks of granite and 

 gneiss, are so exactly alike, that the geologist, who is 

 even long experienced in that country, may traverse 

 them and examine them in every direction, and still 

 remain unsatisfied till he has brought them to the 

 test of his hammer. The very cairns of granite, the 

 piles of prismatic or rounded blocks, are mimicked 

 by sandstone so as to deceive the finest eye, in many 

 parts of the Western coast of Scotland; as its huge 

 curved continuous beds are by the Hypersthene rock 

 of the Cuchullm, and by the greenstone of the Cor- 



