Vol. 58.] | CONSTITUTION OF THE BUNTER PEBBLE-BED. 631 
which he has taken in my work; and to Mr. C. J. Bayzand, of the 
University Museum, Oxford, for preparing the drawings for the 
plates which illustrate this paper. 
EXPLANATION OF PLATES XXXI & XXXII. 
Piate XXXI. 
Figs. 1, 2,5, 6,7, &8. Zircons showing various forms. X 150 to 200 diameters. 
Fig. 3. ‘Capped zircon’ (from a drawing and photograph by Mr. J. B. 
Serivenor). x about 200. 
4. Zircon with basal plane (001). From Burlescombe. x about 150. 
9. Pink stumpy zircon or xenotime (?). x about 150. 
10. Simple crystal of rutile. about 200. 
Figs. 11 & 12. Polysynthetic twins of rutile. about 150. 
Fig. 13. Knee-shaped twin of rutile. X about 150. 
Figs. 14-16. Crystals of tourmaline (brown). x about 200. 
Fig. 17. Basal section of tourmaline, perpendicular to the optic axis. x about 
5) 
-_ 
Prats XXXII. 
‘Figs. 1-5. Tabular erystals of anatase, showing the large base and narrow 
pyramids. X about 225 diameters. 
Fig. 6. Orystal of brookite from the Upper Bunter of Ladram Bay. x 250. 
7. Grains of staurolite, from a microphotograph. X 50. 
8. Group of rudely radiating blue tourmaline, from the Permian 
Breccias (from a microphotograph). x about 150. 
Discussion. 
Prof. Sottas said that the Author had spent much time and labour 
in working out the material of the Triassic sands: he had deter- 
mined the minerals, some not always easy to recognize with 
accuracy ; and his generalizations, when they were not positive facts, 
were at least extremely probable. He had adhered to one horizon 
in his examination of the sands, and this lent additional force to his 
conclusions. 
Mr. H. B. Woopwarp remarked that it was always a source of 
satisfaction to be in harmony with previous observers. According 
to J. W. Salter, many of the Budleigh-Salterton pebbles were 
derived from Normandy ; while Mr. Ussher had observed that north 
of Burlescombe the Triassic conglomerates were of local derivation. 
These views received support from the Author, who had initiated a 
very important line of research. 
Mr. Greenty felt an especial interest in this paper, because among 
the other problems of Anglesey was one concerning certain ‘ Red 
Rtocks.’? Such evidenve as was at present available went to show, 
on the whole, that these were probably of Triassic age, but the 
exposures were very limited. The very interesting and novel results 
obtained by the Author encouraged him to hope that the defects 
of stratigraphical evidence might yet be supplemented by petro- 
graphical data; and that it might, after all, be possible to arrive 
at satisfactory conclusions concerning the relations of these rocks to 
the underlying Coal-Measures, and to the Red Rocks of the Vale of 
Ciwyd and the Western Midlands. 
Prof. Groom said that he was glad to see so interesting an appli- 
