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Geological Society : — 



February 8th.— W. H. Hudleston, Esq., M.A., F.R.S., 



President, in the Chair. 



The following communications were read : — 



1. " Notes on some Coast-Sections at the Lizard." By Howard 

 Fox, Esq., F.G.S., and J. J. H. Teall, Esq., M.A., F.R.S., F.G.S. 



In the first part of the paper the authors describe a small portion 

 of the west coast near Ogo Dour, where hornblende-schist and 

 serpentine are exposed. As a result of the detailed mapping of the 

 sloping face of the cliff, coupled with a microscopic examination of 

 the rocks, they have arrived at the conclusion that the serpentine is 

 part and parcel of the foliated series to which the hornblende- 

 schists belong, and that the apparent evidences of intrusion of 

 serpentine into schist in that district are consequences of the folding 

 and faulting to which the rocks have been subjected since the 

 banding was produced. The interlamination of serpentine and 

 schist is described, and also the effects of folding and faulting. 

 Basic dykes, cutting both serpentine and schists, are clearly repre- 

 sented in the portion of the coast which has been mapped, and these 

 localty pass into hornblende-schists, which can, however, be clearly 

 distinguished from the schists of the country. The origin of the 

 foliation in the dykes is discussed. 



The second part of the paper deals with a small portion of the 

 coast east of the Lion Rock, Kynance. Here a small portion of the 

 ' granulitic series ' is seen in juxtaposition with serpentine. The 

 phenomena appear to indicate that the granulitic complex was 

 intruded into the serpentine ; but they may possibly be due to the 

 fact that the two sets of rocks have been folded together while the 

 granulitic complex was in a plastic condition, or to the intrusion of 

 the serpentine into the complex while the latter was plastic. 



2. " On a Radiolarian Chert from Mullion Island.'*' By Howard 

 Fox, Esq., F.G.S., and J. J. H. Teall, Esq., M.A., F.R.S., F.G.S. 



The main mass of Mullion Island is composed of a fine-grained 

 ' greenstone,' which shows a peculiar globular or ellipsoidal structure, 

 due to the presence of numerous curvilinear joints. Flat surfaces 

 of this rock, such as are exposed in many places at the base of the 

 cliff, remind one somewhat of the appearance of a lava of the 

 ' pahoehoe ' type. 



The stratified rocks, which form only a very small portion of the 

 island, consist of cherts, shales, and limestone. They occur as thin 

 strips or sheets, and sometimes as detached lenticles within the 

 igneous mass. The chert occurs in bands varying from a quarter of 

 an inch to several inches in thickness, and is of radiolarian origin. 

 The radiolaria are often clearly recognizable on the weathered 

 surfaces of some of the beds, and the reticulated nature of the test 

 may be observed by simply placing a portion of the weathered 

 surface under the microscope. 



The authors describe the relations between the sedimentary and 



