PT  - JOURNAL ARTICLE
ED  - , 
TI  - Discussion
AID  - 10.1144/gsjgs.121.1.0354
DP  - 1965 May 01
TA  - Quarterly Journal of the Geological Society
PG  - 354--357
VI  - 121
IP  - 1-4
4099  - http://jgs.lyellcollection.org/content/121/1-4/354.short
4100  - http://jgs.lyellcollection.org/content/121/1-4/354.full
SO  - Quarterly Journal of the Geological Society1965 May 01; 121
AB  - Dr W. R. Dearman welcomed Dr Lambert’s correction of the long-standing misconception on the nature of the Meneage breccias. One of his rock-types, slate with phacoids of greywacke, had been found clearly interbedded with greywacke and slate sequences in exposures of the Gramscatho Series to the west of Pendower Beach in Gerrans Bay. These exposures lay on the presumed north-easterly continuation of the Lizard thrust, and it was clear that both the breccias and the bedded greywackes had been fully involved in the repeated folding that had affected the area. But did the demonstration of the sedimentary origin of the breccias in Meneage and Pendower necessarily negate the concept of a Lizard boundary thrust?The Author replied that the observations made by Dr Dearman were particularly welcome in providing evidence of a sedimentary origin for similar unstratified rocks elsewhere in the so-called ‘crush zone’. The hypothesis of a Lizard boundary thrust could no longer be justified, since it depended almost entirely on the proposition that the Meneage breccias were tectonic in origin.Professor J. Sutton referred to the deformation that could be seen in the crystalline rocks east of Porthallow and the fact that within the sedimentary series described by the author there appeared to be a number of signs of intense deformation. The speaker was inclined to suggest that the earlier structural hypothesis might yet prove to be substantially correct. A history of prolonged but probably intermittent late Pre-Cambrian and Palaeozoic plutonism appeared to be indicated by radiometric age-determinations