486 THE IGNEOUS ROCKS OF PONTESFORD HILL. [NOV. I904. 



The Author had mentioned that the spherulitic type of devi- 

 trification was not all of the same age, and the speaker asked 

 whether this, in part, might be connected with intrusion, as in the 

 well-known instance described by Prof. Bouney. The possibility 

 that these lithophysal rhyolites might be intrusive was a point of 

 considerable interest. 



Prof. Groom drew attention to the apparent resemblance between 

 the rocks described by the Author and those occurring as pebbles 

 in the Cambrian and Silurian Series of the Malvern Hills. 



The Author, in reply, said that he was not aware that the 

 spherulitic structure in the South-Eastern Rhyolite was due to 

 the intrusion of the dolerite. He agreed with Mr. Parkinson 

 that the presence of spherulitic and pyromeridal structures in the 

 Northern llhyolite would be additionally interesting, if the latter 

 turned out to be intrusive ; but the weight of evidence was in 

 favour of its bedded origin. Some years ago the Author collected, 

 and had sliced, a large number of specimens from the ' Warren- 

 House' rocks, on the eastern flank of the Malverns, and he could 

 endorse what Prof. Groom had said with regard to the points 

 in common between them and some of the Pontesford rocks. He 

 thanked the Fellows present for their reception of his paper. 



