Geological Society of London. 377 



Uriconian series, and that the Uriconian series itself (Newer 

 Archasan) was partly formed from the waste of pre-existing rocks. 

 This evidence consisted of (1) the presence, throughout the greatly 

 developed Longmynd conglomerates and grits, of purple rhyolite 

 fragments, recognized by microscopical characters as identical with 

 the Uriconian rhyolites of the Wrekin. and the occurrence of grains, 

 probably derived from the same rhyolites, in the typical green slates 

 of the Longmynd ; and (2) the existence of conglomerate beds con- 

 taining rounded fragments of granitoid rock in the core of the 

 Wrekin itself, whilst the Uriconian beds of other localities, and 

 especially those of Charlton Hill, contained waterworn pebbles, 

 chiefly metamorphic. These pebbles appeared to have been derived 

 from metamorphic rocks of three distinct types. The views put 

 forward were founded on microscopical evidence, of which some 

 details were given in the paper, and were supported by the views 

 of Professor Bonney, who had furnished notes on the microscopical 

 characters of the rocks. 



3. "Notes on the Relations of the Lincolnshire Carstone." By 

 A. Strahan, Esq., M.A., F.G.S. 



The Lincolnshire Carstone has hitherto been supposed to be 

 correlative with the upper part of the Speeton series, and to be quite 

 unconformably overlain by the Red Chalk (Quart. Journ. Greol. Soc. 

 vol. xxvi. p. 326-347). But the overlap of the Carstone by the 

 Red Chalk, which seemed to favour this view, is due to the northerly 

 attenuation, which is shared by nearly all the Secondary rocks of 

 Lincolnshire. Moreover, the Carstone rests on different members 

 of the Teal by group, and presents a strong contrast to them in litko- 

 logical character, and in being, except for the derived fauna, entirely 

 unfossiliferous. It is composed of such materials as would result 

 from the " washing " of the Tealby beds. 



In general it is a reddish-brown grit, made up of small quartz- 

 grains, flakes and spherical grains of iron-oxide, with rolled phos- 

 phatic nodules. Towards the south, where it is thick, the nodules 

 are small and sporadic. Northwards, as the Carstone loses in 

 thickness, they increase in size and abundance, so as to form a 

 " coprolite-bed," and have yielded specimens of Ammonites speetonensis, 

 A. plicomphalus, Lucina, etc. When the Carstone finally thins out, 

 the conglomerate character invades the Red Chalk, similar nodules 

 being then found in this rock. 



The presence of these nodules, with Neocomian species, taken in 

 connexion with the character of the materials of the Carstone, points 

 to considerable erosion of the Tealby beds. On the other hand, 

 there is a passage from the Carstone up into the Red Chalk. It 

 would seem, then, that the Carstone should be regarded as a " base- 

 ment-bed " of the Upper Cretaceous rocks. 



The Lincolnshire Carstone is probably equivalent to the whole of 

 the Hunstanton Neocomian, the impersistent clay of the latter being 

 a very improbable representative of the Tealby Clay. It therefore 

 follows that the whole Speeton series is absent in Norfolk, and also 

 in Bedfordshire. The unconformity at the base of the Carstone 



