Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. I3I 



southern, i. e. for the metamorphic area over and above that of the 

 beds farther north, i. e. for the unmetamorphosed Devonians. But 

 perhaps the most unsatisfactory feature in his argument is exhibited 

 by his calling in the aid of magnesia and carbonic acid from out- 

 side sources in order to account for these processes of metamorphism 

 which seem to him so easy. ' Meantime, Prof. Bonney expresses 

 himself yet more confidently than in his original paper as to the dis- 

 tinction in lithological characters and age between the two groups 

 of rocks, viz. the metamorphic schists and the slaty Devonian system. 

 Judging, however, from statements in one of his Channel Island 

 papers, it would seem that he regards the Start Schists as belonging 

 to the group of metamorphosed sediments rather than to that of 

 schistose igneous rocks. But whatever his views may be, we can 

 confidently predict that the schists of the Start, like the granite of 

 Dartmoor, will still continue to exercise the critical functions of 

 the Devonshire geologists, unless some indisputable stratigraphical 

 evidence should happily settle the controversy. 



The Lizard. — There have been four papers from well-known 

 authors dealing with this much-debated peninsula. In the first 

 paper Mr. Howard Fox described the gneissic rocks which lie off 

 the Lizard. There are three groups, he observed, apparently 

 forming a sort of gradation from the outermost coarse gneisses, 

 through light, banded, granulitic gneisses to the transition micaceous 

 rocks of the inner reefs, which still more nearly approach the 

 mainland schists. The inclination of the divisional planes appears 

 onformable with that of the rocks of the mainland. The gneisses 

 and granulites are traversed by numerous dykes of porphyritic basic 

 rock. There are some valuable petrographic notes to this paper by 

 Mr. Teall. It was held that the period of dynamic metamorphism, 

 of which the most striking results are seen in the south-western 

 portion of the Lizard peninsula, was posterior to the formation of 

 the basic dykes, and that there is no evidence of igneous action in 

 the district since the period of metamorphism. 



General M c Mahon next contributed some notes on the Horn- 

 blende Schists and Banded Crystalline Rocks of the Lizard. In 

 conformity with the views of De la Beche, J. A. Phillips, and 

 others, he considered that microscopic study proved the schists to 

 have had a volcanic origin, and to consist principally of ash-beds ; 

 and he further maintained that there is no evidence that the 

 foliation of these rocks is due to dynamic deformation. The Author 



