Here then is the phenomenon which has invested the spot with so much geological interest. Here is _Granite_, which _Werner_ conceived to be a primary formation, and around which he supposed all other rocks to have been deposited, if not of a later date, at least contemporaneous, in origin, with slate. How is this anomaly to be explained? _De Luc_ at once asserts what we presume no rational observer can for one moment believe, that the rock of which these veins are composed is _not_ true Granite, but "_Pseudo-granite_"! _Dr. Berger_ attempts to surmount the difficulty by a different expedient, and declares that _they are not veins!_ but prominences from the granite beneath, which have been filled up by the subsequent deposition of clay-slate. It might, says _Sir H. Davy_,[25] with nearly as much reason be stated, that the veins of copper and tin belong to a great interior metallic mass, and that they existed prior to the rocks in which they are found. The advocates of the Plutonian theory have, as might have been supposed, eagerly availed themselves of the support which this phenomenon is so well calculated to afford their favourite doctrine. They accordingly affirm that the granite has been raised up through the incumbent slate, into whose fissures it has insinuated itself. Upon these theories we shall offer no comment; it is the humble task of a "Guide" merely to direct the attention of the traveller to the phenomena themselves, and then to leave him to deduce his own conclusions from their appearance. In the fulfilment of this duty we recommend the geologist to proceed to the western base of the Mount, where he will find near the water's edge, what have been considered by _Dr. Thomson_ as "two large beds of granite in the slate, with veins running off from them; the position and appearance of which are such as to leave no doubt but that the great body of the granite has been deposited posterior to the slate formation." _Mr. Carne_, on the other hand, contends that "these granitic bodies cannot with any propriety be called '_Beds in the Slate_;' one of them," says he, "is a granite vein, and although six feet wide near the granite mass, it becomes gradually smaller as it recedes, and dwindles to a point at the distance of 80 feet. The other is a part of the granitic mass, from which some veins appear to diverge; and, in _no part_ does it overlie the slate."[26]