Vol. 50.] ANNIVERSARY ADDRESS OP THE PRESIDENT. l$$ 



Lizard Rocks was furnished last session by Messrs. Fox and Teall, 

 who gave a very close description of two limited districts, viz. that 

 of Ogo Dour and that of the Lion Bock near Kynance. In the 

 former district they conclude that the hornblende-schist and ser- 

 pentine form together a bauded complex of crystalline foliated 

 rocks, and that if there is any material difference in age the 

 serpentine is likely to be the earlier of the two. This, it should be 

 stated, is an olivine-hornblende serpentine, markedly different from 

 the common variety. The complex of schist and serpentine has been 

 folded after the banding was produced, and before the dykes were 

 intruded, whilst some, if not all, of this folding probably took place 

 when the complex was formed. The schist and the serpentine are 

 traversed by dolerite- dykes, which have themselves been converted 

 into schists, macroscopically indistinguishable from portions of the 

 normal hornblende-schist of the Lizard peninsula ; faulting has 

 taken place after the dykes had reached their present condition. 



In the Lion B,ock district the relations between the serpentine 

 and the ' granulitic ' group are considered. The main mass of the 

 cliff here is formed of serpentine, of which the common variety 

 weathers red and contains numerous crystals of bastite. Basic 

 dykes and a gabbro-vein are observed to traverse this, and these 

 dykes pass occasionally into hornblende-schist. Moreover, they 

 vary in thickness, and in some of the thicker portions put on 

 appearances which are characteristic of the 'granulitic' group. 

 In the section a wedge-shaped mass of typical ' granulitic ' rock is 

 seen surrounded by serpentine, and the structure of this mass 

 appears to be incompatible with the theory that the serpentine was 

 intruded into it when solid. 



As an interesting appendage to this paper the same Authors gave 

 an account of a Badiolarian Chert from Mullion Island, with the 

 addition of critical notes by Dr. Hinde. This paper might indeed 

 have been included in the Palseontological division, but as a matter 

 of convenience it is placed along with the rest of the communications 

 relating to the Lizard. The stratified rocks, which form only a 

 small portion of the island, consist of chert, shales, and lime- 

 stone, occurring as thin strips or sheets and sometimes as detached 

 lenticles within the prevailing mass of ' greenstone/ possibly repre- 

 senting a subaqueous lava. The chert is of radiolarian origin, 

 and the radiolaria are often recognizable on the weathered surface 

 of the beds. Dr. Hinde gave a technical description of the re- 

 cognizable forms, the genera being included under the suborders 



vol. l. /• 



