322 MR. 0. A. SHEUBSOLE Otf TRIASSIC PEBBLES OF [Aug. I903, 



but paler in colour, and more like the Gres feldspathique of the Cherbourg 

 district. The latter, which is less well preserved, is considered to be about the 

 age of the Linguta-Flags (Tremadoc not distinguished), the overlying quartzite, 

 which is very like the Stiper-Stones quartzite, being referred to the Arenig 

 Series. 



'Microscopic characters. — Some of the grains are fairly rounded, and 

 some are composite. There is microcline among the felspar. Very like some of 

 the Torridon Sandstone of Scotland ; also resembling the Bunter quartz-felspar 

 pebbles, which, however, are generally rather less well preserved. 



'3. [A bright red pebble taken from the beach at Budleigh Salterton. 

 Although flattened by marine action, it was obviouslv derived from the pebble- 

 bed.] 



' Hand- specimen. — A typical Salterton pebble, rather paler than the 

 liver-coloured, and I think a little different ; nearer to the ordinary white 

 type. 



'Microscopic characters. — A fine-grained more grit -like quartzite than 

 the usual Bunter type. Certainly contains tourmaline (brown). I do not 

 think the microscopic distinction very strongly marked.' 



I may remark that I selected the last-named specimen, because 

 of its being of a particularly bright-red colour. The resemblance of 

 hand-specimens, as will have been seen by the examples submitted, 

 is very close and striking. 



There is another very characteristic pebble found at Budleigh 

 Salterton as well as in the Midlands, namely, a veined black grit, 

 formerly known as lydi an stone, and now generally known as a 

 tourmaline-grit. The general impression is that the rock comes 

 from Cornwall, as it appears to be unknown in the northern districts. 

 I was not so fortunate as to find any of it in situ in Normandy, but 

 I find a reference in MM. G. de Tromelin & P. Lebesconte's work l 

 to a black quartzite veined with white ('quartz-lydien') occurring 

 in the department of Maine-et-Loire, and containing graptolites of 

 Llandeilo age. 



Putting all these facts together, we find that there are, or 

 probably have been, rocks in Normandy which will account for a 

 very large number of the Budleigh-Salterton pebbles. On the 

 other hand, rocks which are not represented in the pebbles to any 

 appreciable extent, either do not occur in Normandy, or if they do 

 occur (as in the case of the Phy Hades de St. L6) they were probably 

 covered by other deposits, and were not undergoing erosion in 

 Triassic times. The connection is too close to be accidental ; there- 

 fore it appears a reasonable conclusion that the mass of the 

 Budleigh-Salterton pebbles has been derived from 

 some part of the ancient Armorican highlands. If they 

 were brought by a single large river, that river doubtless drained 

 a considerable area, including probably the Calvados district of 

 Normandy, part of the Channel area, and possibly part of Britanny, 

 and the general direction of its flow must have been northward. 



1 G-. de Tromelin & P. Lebesconte, ' Essai d'un Catalogue raisonne des 

 Fossiles siluriens des Departements de Maine-et-Loire, de la Loire-inferieure 

 & du Morbihan,&c.' C. B. Assoc, franc;. Avancem. Sci. (Nantes) 1875. 



