TRANSACTIONS OF SECTION 0. 737 



the limestone area west of the dry valley ; and under certain conditions some of 

 the Tarn water. 



2. That Aire Head Springs discharge the main portion of the water disappear- 

 ing down Malham Tarn Water Sinks. 



3. That Gordale Beck Springs discharge the water sinking in Upper Gordale. 



4. That chemicals put into Cawden ' Burst ' appeared at Mire's Barn. 



5. That Tranlands Beck Sinks discharge at Scalegill Mill, 



6. The investigations show that within the area the main direction of under- 

 ground flow is along the master-joints of the limestone.^ 



6, Report on the Movement of Underground Waters of Craven. The 

 Ingleborough District. — See Reports, p. 346. 



7. On Ancient Plateaux in Anglesey and Carnarvonshire. 

 Bij E. Greenly, F.G.S. 



The surface of Anglesey, considered as a whole, is seen to be composed of a 

 series of broad ridges ranging N.E. and S.AV., and so remarkably even in height 

 as to leave little doubt that they are really portions of an undulating plateau 

 about 200-300 ft. above the sea. Holyhead Mountain and about four other hills 

 rise abruptly above the general level. This plateau is traversed, not bounded, bv 

 the Menai Straits, beyond which it ranges to the foot-hills of the mountain region, 

 where a totally different type of scenery begins. The protile of this mountain 

 region appears, when viewed from the N.W., as that of a very gentle flattened 

 dome, rising gradually from Penmaenbach, on the N.E., till it attains a height of 

 more than 3,500 ft. in the Carnedds and Snowdon, and declines again as gradually 

 to Yr Eifl and Carn Boduan, in the far S.W. This, therefore, and the Ano-lesey 

 plateau, would appear to be ancient platforms or base-levels ; and they also appear 

 to be distinct. 



That of Anglesey must be at least of post-Carboniferous age, for Carboniferous 

 and older rocks are levelled off indiscriminately at its surface, and if the Red rocks 

 of the island are Permian or Triassic it must be of Mesozoic, possibly of Cretaceous, 

 age. The age of the platform bounding the mountain region is more difficult to 

 determine. It is tentatively suggested that this feature may pass below the 

 Carboniferous rocks, and so be really a deeply denuded sub-Carboniferous base-level 

 rising as the core of a broad anticlinal. 



8. On the Form of some Rock-bosses in Anglesey. 

 By E. Greenly, F.G.S. 



The general trend of the major axis of the bosses that are so marked a feature 

 of the land surface in Anglesey coincides as a rule with the strike of the dominant 

 structures, which is for the most part N.E.-S.W. But slight discordances are not 

 uncommon ; and in some cases, particularly among the hornblende gneisses about 

 Craig-y-Allor, the bosses trend iu the usual N.E.-S.W. direction, in spite of the 

 fact that the banding of the gneiss strikes almost N.AV.-S.E., i.e., very nearly at 

 right angles to this. 



9. The Concretionary Types in the Cellular Magnesian Limestone of 

 Durham. By G. Abbott, M.R.C.S. 



Associated with the Cannon-ball bed near Sunderland is a cellular limestone 

 which is much more extensive, and exhibits still more remarkable physical 



' The complete report, fully illustrated, will be published in the ProCeedino-s of 

 the Yorkshire Geological and JPolytechnic Society, Vol. XIV., Part I, ° 



1900. 3 B 



