Rev. J. F. Blake — The Llanheris Unconformity. 221 



represented, tliere were an anticlinal bere, the junction would 

 naturally take place over its crest ; but of such an anticlinal no one, 

 from Sir A. Ramsay onwards, bas ever been able to find a trace, and 

 it is now abandoned even by Professor Bonney and his coadjutor. 

 From these considerations and others to follow I hold that an 

 imconformity is the only alternative left, whatever may be the 

 teaching of Professor Green's section. 



This section, seen on the tramway, has been differently inter- 

 preted by my critics and myself. If my opponents' reading 

 of it be correct, I should say with one of them that the 

 unconformity was only locally absent; .if mine be correct, it will 

 afford only confirmatory evidence, valuable, no doubt, but not 

 essential. My critics, however, try to give it an unmerited 

 importance. They " are told," they say, " that here the hypothesis 

 can be brought to a direct test." They were certainly never told so 

 by me. No hypothesis can become a conclusion without being 

 subject to many tests, and a single section, with the possibility of 

 a local absence of unconformity, is not suitable for a " final appeal." 



To me the evidence of this section is clear enough, but Sir A. 

 Eamsay, Sir A. Geikie, and Miss Raisin are all against me, and 

 I have only the support of Professor Green,'^ a good stratigraphist. 

 With regard to this support, it is not fair of my critics to say 

 that " the only line which might be supposed, and has been 

 supposed by Professor Green, to mark it [the unconformity] is not 

 shown by Mr. Blake," when I distinctly said that " his description 

 is so wonderfully true to nature that I could only quote him 

 verbatim," including, of course, his diagrams. My general diagram 

 was intended only to illustrate my view of the general relations, 

 just as was Professor Bonney's. 



I do not think the line which those who see conformity here have 

 noticed some way down in the breccias is really a line of bedding. 

 I can see there no change of material, but of course I may be wrong. 

 But if so, there still remains the cleavage. Now cleavage, as Dr. 

 Hicks pointed out, had already been pi'oduced in the district before 

 the conglomerate, containing cleaved pebbles, was formed. Nor do 

 I see how the angular fragments in the underlying breccia could 

 have been turned round, thereby shortening the horizontal dimension 

 of the rock, after the conglomerate was there, and yet leave an 

 imdiilating, closely-welded line between the two rocks, seeing that 

 the conglomerate has not been shortened, and the line of junction 

 is, at least in places, perpendicular to the cleavage. Hence, whether 

 from bedding or cleavage, I think the breccia fragments were 

 made vertical before the deposit of the conglomerate. 



Again, my critics say that " the ' nearly horizontal line ' does 

 not exist." As to this, it must be remembered that for two rocks to 

 be conformable they must be conformable everywhere, but to be 

 unconformable they need only be unconformable anywhere. It is 

 thus quite enough for the purpose that my critics themselves 



1 Professor Hughes and Dr. Hicks accepted the uuconformity, but I do not know 

 that they have personally observed it. 



