Tol. 55.] STEUCTUEE OP THE SOUTHEEN MALVEENS. 169 



deposits of Cambrian or Silurian age, or intrusive masses invading 

 Cambrian or Silurian rocks. In each case, the mistake seems to 

 have been mainly due to the fact that the observers had failed to 

 recognize the remarkable results produced by faults and crushing, 

 not only on the sedimentary beds in the immediate neighbourhood 

 of the pre-Cambrian crystalline rocks, but also on the latter, during 

 intense movements in the earth's crust. 



Prof. SoLLAs remarked that ever since Phillips had made the 

 MalTisrns the base of the district described in his ' Geology of 

 Oxford & the Valley of the Thames,' those mountaius had been a 

 source of peculiar interest in Oxford, and the Author's work had 

 been looked forward to with great expectations, which the paper of 

 that evening had more than satisfied. It presented them with 

 an epitome of mountain-structure, logically worked out, even 

 the transverse fractures, which must necessarily result in crust- 

 folding, receiving the attention which they merited, but rarely 

 obtained. The examples of ' basalt ' exhibited did not appear to be 

 typical examples of that rock ; and since nearly every petrographer 

 used the term 'diabase' in a different sense, the speaker thought 

 that this name should not be employed without some qualification. 

 With regard to the nodes and internodes of the West English chaiu, 

 it was possible that the two systems of crossing folds which produced 

 them might have been simultaneous, and not successive. 



Prof. Watts referred to the igneous rocks associated with the 

 Cambrian rocks of the Malvern Hills, and noted their resemblance 

 to those originally described by AUport as diorite in Warwickshire. 

 Similar rocks occur in association with Cambrian strata at Nuneaton, 

 the Longmynd, the Wrekin, and in the Northern Highlands. 



The Peesident, Prof. Lapwoeth, Prof. Bonnet, and Prof. Hull 

 also spoke. 



The Atjthoe said, in answer to Prof. SoUas and Prof. Watts, that 

 the terms ' basalt ' and ' diabase ' were employed in the sense used 

 in Mr. Harker's ' Petrology for Students.' To Prof. Lapworth he 

 replied that he hoped to deal in a later communication with the 

 movements which the Malvern chain had undergone. 



