120 Rqiort on the Moel Tryfaen Drift. 



by slipping, the junction with the sandy drift above is usually 

 well marked, but angular and subangular debris is mixed with the 

 lowest layers of the gravel. 



Conclusion. — The above description is not intended to be ex- 

 haustive, though the description of the section about to be destroyed 

 has been made as full as seemed possible at the time. Incidentally 

 certain details in other parts of the quarries were observed, and 

 have therefore been included ; but these form only a subsidiary 

 and unessential portion of the report, and are therefore placed in 

 a separate appendix,^ because the sections in which they are 

 displayed are in no danger of destruction. Generally, moreover, 

 it will be observed that the report is confined to questions of 

 structure, physical relations, and measurements ; and that many 

 matters of the highest importance, such as species, distribution, and 

 state of preservation of the shells, the nature of the boulders in the 

 sands and the clay, the character of the fine material of the drifts, 

 are not dealt with. These are points which can be investigated as 

 well as ever in extensive sections, which the quarrying will keep 

 clear and open. 



It must not be supposed that the Moel Tryfaen sections are being 

 destroyed as a whole. It is the part specified only that is perishing ; 

 and the drifts of the quarries will continue to furnish ample scope 

 for research into many matters of great importance to glacial 

 geology for many years to come. 



Note A. — By Chairman and Members. 



(a) §10. — Some of the best preserved specimens sent to me by 

 Mr. Menzies from the drift in the Alexandra Quarry have adhering 

 to them a fine loamy sand, and it is in such a material, interstratified 

 with sand and gravels, that I have usually obtained the best 

 specimens of shells in the Welsh sections. — H. H, 



(/3) § 10, — In addition to boulders of North Welsh rocks, they 

 are full of far-travelled erratics from the Lake District and the 

 South of Scotland. 



(o^) § 11. — This deposit, therefore, differs widely in regard to its 

 included stones from the underlying sandy group, which contains 

 many far-travelled erratics, as befoi'e stated ; as it does also in the 

 apparent absence of marine shells and of Foraminifera. 



(B) § 13. — P. F. Kendall and J. Lomas would prefer to say that 

 the general direction of displacement had only a few individual 

 exceptions, which might indeed be due to quarrying operations. 



(c) § 13. — This material was not observed by the Committee to 

 contain any glacially striated fragments or any foreign stones — no 

 fragments, indeed, but of the underlying slates. 



Note B.—By T. Mellard Reade, F.G.S. 



Specimens of the drift were taken by me at the meeting on 

 November 5, 1898, in the positions shown on the following sections 



1 See Appendix C. 



