Vol. 52.] BOCKS OP THE LIZAED DISTEICT. 51 



to the pressure which had resulted in the marked plication which 

 they both now exhibited. 



Mr. J. H. Collins said that he had not visited the district referred 

 to by the Author for a dozen years or more, so that his recollection 

 •of the facts upon which his opinion was based was rather hazy. He 

 had, of course, read the able papers which had been presented to the 

 Society by several eminent geologists in that period, but had not felt 

 -called upon to alter in any important particulars the opinions which 

 he had expressed in 1 885 in the ' Geological Magazine.' It was 

 remarkable that so small an area should afford grounds for so great 

 a diversity of opinion : there were almost as many opinions as parties 

 of observers. There were, indeed, some indications of approximation 

 of divergent views ; but the approximation was so small during 

 the eighteen years which had elapsed since the reading of Prof. 

 Bonney's first paper, that he feared no one then present would live to 

 witness the general acceptance of the one and only right view which 

 would embrace all the facts. 



The Authoe said in reply to Mr. Teall that, from the remarks of 

 the latter, it appeared that he still adhered too much to the principle 

 which he (the speaker) thought likely to mislead — namely, restricting 

 the attention to single sections, and dwelling on the minor difficulties 

 presented by them, without regard to the evidence in other parts of 

 the district. Of this the speaker pointed out instances. He thought 

 that Mr. Teall had overstated the amount of banding visible in the 

 serpentines of the Mullion — Ogo-dour district ; as a rule (except in 

 the cases mentioned by the Author — what he considered to form a 

 mixture of the two rocks), it was only foliation. As for the 

 Norway peridotites, certain things had been asserted of them, 

 but not proved. Such bending as there was of the rocks about 

 Potstone Point could not be the result of flexure by ordinary 

 mechanical forces ; nor could this cause the ' flaser ' structure in the 

 gabbros of the east coast. In the former case the weld of the ser- 

 pentine and hornblende-schist would have been destroyed ; in both 

 the serpentine would have been much broken, in the latter crushed, 

 for gabbro is one of the toughest of rocks. On this point his 

 experience in the Alps enabled him to speak with confidence. 



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