602 FRAGMENTAL ROCKS IN N.W. CAERNARVONSHIRE. [Nov. 1 894, 



pre-Cambrian ridge at Caernarvon. The paper in his opinion gave 

 the death-blow to the views put forward by Prof. Blake in regard 

 to the succession of the older rocks in Caernarvonshire. 



Mr. Whitaker also spoke. 



Prof. Bonnet replied that if Mr. Blake meant that another 

 conglomerate was to be seen in the adit at Moel Tryfaen besides the 

 one described by the Authors, it was in favour of their hypothesis 

 of a fault. He could not admit that the felsite and purple slate 

 were ' zigzagged together,' as Mr. Blake described. If the Authors 

 had found the right place, the rock was not felsite but a felsitic 

 grit. In the alleged unconformity by the slate-railway, the struc- 

 ture in the ' rain-spot breccia ' was due to cleavage, not to bedding. 

 Cleavage often disappeared in passing from finer to coarser strata — 

 that was a matter of common experience. Moreover, cleavage 

 could be just traced in the Conglomerate, and was perfectly 

 developed in some interbanded fine grits or mudstones, a few steps 

 uphill above the crag depicted. In answer to a question asked, 

 he might remark that the Authors had carefully avoided the pre- 

 Cambrian question, as foreign to the immediate issue of their 

 paper, so he must decline to express his opinion on the subject. 



