OF CENTRAL AND EASTERN CORNWALL. 497 



against the old idea of the greater age of hornblendic as compared 

 with pyroxenic rocks, which was gradually being upset. He thought, 

 however, that there was still much to be made out with respect to 

 the intrusion of these igneous rocks. 



Prof. Bonnet said that he had frequently observed the same con- 

 version of augite into hornblende described by Mr. Phillips, in Corn- 

 wall, Wales, and Charnwood, and in continental rocks. He quite 

 agreed that the Duporth rock was not a true serpentine. 



Mr. Sollas stated that he had obtained from near Dartmoor spe- 

 cimens of rocks confirmatory of Mr. Phillips's statements. He 

 inquired whether any connexion could be established between the 

 greenstones and granites. 



Prof. Ramsay expressed his gratification at the thorough-going 

 nature of the author's researches, and was especially pleased that 

 Mr. Phillips had found that many of the rocks exhibited such close 

 resemblance as to justify the use of the term " greenstones." 



The Author, in reply, stated that the greenstone dykes often 

 seemed to differ in age ; but he had seen cases in which one appeared 

 to have been plastic when the other was introduced. 



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