﻿-372 THE REV. J. F. BLAKE ON THE [May I905, 



blades of grass grow where one grew before can in no way injure 

 the credit of him w 7 ho first made the first grass grow, and compared 

 it with a ' crush-conglomerate.' 



Discussion. 



Mr. Lamplugh said that he strongly appreciated the kindly 

 attitude of the Author, and recognized the pains which had been 

 bestowed upon the investigation. But, after full consideration of 

 the evidence brought forward by the Author, he found it necessary 

 still to adhere to his previous interpretation, both of the succession 

 and of the crush-conglomerate. In studying this extremely-com- 

 plicated area the Author had placed far too much confidence in 

 apparent dips, which had been shown to be misleading as indications 

 of the sequence ; and he had also called in faults to his aid, without 

 any proof that these faults were of more consequence than the 

 innumerable other fractures by which these rocks were traversed 

 that apparently had no structural significance. 



The speaker was well satisfied to find that three parts of the 

 sequence proposed by him had been accepted by the Author, who, 

 however, washed to reverse the order of the one remaining part by 

 postulating a great unconformity, for which no acceptable evidence 

 was forthcoming. All the facts known to the speaker were utterly 

 opposed to the view that there could be an unconformity between 

 the Lonan or Marbyl Flags and the rest of the Manx-Slate 

 Series. 



As for the crush-conglomerate, the speaker did not feel called 

 upon to defend the definitions of other workers : he relied entirely 

 upon the field-evidence in the Isle of Man, which he held to be 

 convincing for the ' autoclastic ' origin of the fragmental beds. The 

 disrupted strata were not homogeneous, but a mixture of laminated 

 slates and gritty greywackes; and he failed to find any other 

 material among the specimens exhibited on the table. The Author 

 acknowledged the autoclastic structure in that portion of the crush- 

 conglomerate where disruption was incomplete, but denied it for 

 the portion in which the process had gone a step further. 



The speaker admitted that there was room for further work in 

 the Manx Slates, but he was doubtful whether the present attempt 

 had really advanced our knowledge of this extraordinarily-difficult 

 series. 



Mr. Barrow, who said that he had seen part of the area discussed, 

 in company with the previous speaker, agreed with his interpreta- 

 tion of the nature and origin of the crush-conglomerate. But this 

 rock differed somewhat from the commoner type, in which the 

 matrix and the pseudo-pebbles had the same original composition. 

 In the case described by Mr. Lamplugh, the pseudo-pebbles were 

 embedded in a matrix originally of softer composition. The 

 exceptionally-large scale on which the phenomenon had occurred, 

 was probably due to the original nature of the rocks and their order 

 of superposition. A thick bed of soft shale was underlain by a 



