906 



THE WONDERS OF GEOLOGY. Vol. II. 



microscopic examination into the condition of silica, might lead to the 

 discovery of elementary organic forms, even in the primitive strata 

 themselves. It was obviously not necessary to exclude granite from 

 this examination, under the common and apparently natural impres- 

 sion, that the igneous fusion which preceded the present arrangement 

 of its particles, would destroy every trace of organization; for I had 

 befo e me too many manifest proofs, that an intense white heat, 

 though capable of fusing glass, was incapable of effecting any change 

 in the minute siliceous organization both of plants and animals. 

 Moreover, there appeared to be a strong suspicion in some minds, 

 that every successive surface of our globe had been characterized by 

 its own minute living forms; and you, yourself, had more than once 

 contended for the probability of the existence of life during the most 

 anc : ent granitic period of which we are able to obtain any indications. 

 To give a reality, however, to & first condition, thus pronounced to be 

 probable, we must discover the skeletons of animalcules even in 

 granite itself. But here arises a difficulty which will baffle our utmost 

 ingenuity to remove ; for, though on the one hand, I meet with 

 siliceous corpuscles in the primitive rocks, and find, on the other hand, 

 that the indestructible organic skeletons of recent Infusoria exhibit, 

 even under a power of 900 linear, a striking similarity of form, yet the 

 entire absence of external structure precludes me from assigning a 

 common animal origin to the ancient and recent structures. Still, 

 the inquiry, even in its present state, is far from being fruitless ; for 

 it cannot but be a matter of surprise, that immense mountain masses 

 should have been found to consist of an aggregation of symmetrical 



bodies, between K — nft and 77^™ th of an inch in diameter, articulated 



7 5,000 10,000 > 



together in the form of rings or of slender threads, as in limestone, and 

 the quartz of granite : and that an exact counterpart of this curious 

 structure in the mineral kingdom should be exhibited in the vege- 

 table, by the mouldiness of paste, and in the animal by the Gaillonella 

 ferruginea." 



D. Page 880. — Parallel Terraces of Glen Koy. — I am induced to 

 notice, in this place, a remarkable phenomenon observable in some of 

 the glens of the Highlands that border the Great Caledonian Valley, 

 because the subject has excited the attention, alike of the tourist and 

 the geologist. In several of the glens of Lochaber, but more especially 

 in that of Glen Roy, there are parallel terraces, at various heights, 

 extending on either side ; and which present so regular and artificial 

 an appearance as to have been ascribed to human art : and the ancient 

 Highlanders supposed them to be roads formed by their hero Fingal. 



The valley of Glen Roy is of an oval form, and is about four miles 

 long, and one or more wide, being bounded on two opposite sides by 

 high mountains. Through the middle of this valley, a river, formed 

 by the confluence of some mountain-streams, flows into the Spean 

 water. 



