288 MONTHIiT MEETINGS. 



April 18^, 1887. 



Mr. Thomas Clark read a paper "On the Igneous Rocks of 

 Cornwall, suitable for building purposes," and dwelt particularly 

 on the diorites, gabbros, granites, and other felspathic 

 rocks, pointing out their qualities, mineral characteristics, 

 microscopic aspects, and their behaviour under the polariscope. 

 Especial reference was made to the Duporth and St. Mewan 

 rocks. 



This interesting session was brought to a close on the 

 2nd May, 1887, when the Members gave a conversazione, which 

 was well attended, and subjects of much interest relating to 

 objects in natural history occurring in the immediate neighbour- 

 hood of Truro, were brought to the notice of the Meeting. 

 Specimens also of interesting objects were exhibited, and 

 amongst them Mr. J. Snell showed a fine specimen of the 

 gorgonia verrucosa. Mr. J. H. James exhibited a collection 

 of shells illustrative of the various genera in conchology; 

 Mr. Blenkinsop some rare plants, and Mrs. Paull of Bosvigo a 

 beautiful collection of otoliths. Before separating, the thanks 

 of the society were especially given to Mr. J. Snell and 

 Mr. J. H. James, who were the organizers of the society, and on 

 whom devolved the arrangements for the meetings. It was 

 decided that a series of excursions for furthering the objects of 

 the society should be made by land and water during the 

 summer months. 



