ANNIVERSARY ADDRESS OF THE PRESIDENT. IxXXV 



ceous limestone, about 500 feet. The upper gneiss is represented as 

 sometimes different in character from the lower, occurring in thin beds, 

 often curved and twisted, and when near the porphyry, fine-grained, 

 almost compact and composed chiefly of quartz with a little felspar 

 and minute scales of mica. This gneiss indeed is supposed to be a 

 rock metamorphosed m situ, and the metamorphic action is pre- 

 sumed to have extended downwards to the argillaceous beds of the 

 quartzite series. In touching upon the subject of metamorphism, 

 we may perhaps assume that a true gneiss in which crystallization 

 is perfect, and where the difference between it and granite is little 

 more than the laminated or bedded structure which it exhibits, must 

 be looked upon, if metamorphic at all, as the most perfect form of a 

 metamorphic rock, but in the rock here described there is little ap- 

 proach to that type ; the great difficulty, however, must ever be to 

 account for a metamorphism in a rock quietly resting upon others, 

 in which the evidence of such process is at least very feeble. Every 

 day, however, is bringing such cases before us, and, though the diffi- 

 culty cannot be considered overcome, we must receive the facts with- 

 out hesitation, though we may be unable to account for them. In 

 the limestone some obscure fossils have been discovered, one sup- 

 posed to be a Euomphalus, and another a Lithodendron ; notwith- 

 standing the uncertainty which hangs over their determination. Pro- 

 fessor Nicol thinks he has reason to consider the limestone beds con- 

 taining them and the quartzite, to belong to the carboniferous epoch, 

 and the underlying sandstones to the Devonian. In this con- 

 clusion, he is opposed to Sir Roderick Murchison, who considers these 

 rocks Silurian ; nor does Professor Nicol evade the difficulty con- 

 sequent on the position of the gneiss in the central region of Ross and 

 Sutherland, which passes under the Old Red Sandstone of Ross-shire 

 and Caithness, but states his conviction that there are several depo- 

 sits of Red Sandstone and conglomerates of different ages; and, 

 further, that he does not consider that any proof has as yet been 

 given of the identity of the underlying gneiss of the east coast with 

 the overlying gneiss of the west, but rather perhaps that the lower 

 gneiss of the west may be the representative of the eastern gneiss, 

 having been pushed up amongst deposits of different ages. Though 

 no one can doubt the accuracy of Professor Nicol' s field work, and 

 though, I may add, there is no impossibility in his deduction from it, 

 even his own words justify me in saying that the subject still requires 

 further examination. The references to glacial action, as exhibited 

 in local accumulations of drift, in highly polished surfaces of rock, 

 and in detached "perched blocks," are interesting as extending our 

 knowledge of such facts, but are hardly sufficient to prove any con- 

 siderable elevation of the Highlands above their present level, followed 

 by a subsidence and then by a later partial elevation. I cannot but 

 think that more caution is necessary in dealing with such great 

 phsenomena. 



The great work of Guido and Fridoiin Sandberger, on the Rhenish 

 Provinces of Nassau, has now been brought to a close by the publi- 



