Geological Society of London. 379 



ancient glaciers, being thus of the nature of " giants' kettles," though 

 on an enlarged scale. 



7. "Diorites of the Warwickshire Coal-field." By S. Allport, Esq. 

 The diorites are intrusive in the lower and unproductive measures 



of the above field and the underlying Millstone- grit below Atherstone 

 and Marston Jabet (two miles south of Nuneaton). The author 

 describes their microscopic characters. One variety is very finely 

 crystalline and contains brown hornblende. Another contains plagio- 

 clase felspar with a little orthoclase, small crystals of brown hornblende, 

 many crystals of clear yellowish augite, and several pseudomorphs 

 after olivine, with apatite, magnetite, etc. A mineral also occurs 

 belonging to the hexagonal system, which the author suspects to be 

 nepheline. Other varieties are described, one of which contains 

 augite with hornblende. These rocks differ considerably from the 

 syenites of Leicestershire. 



8. On Lepidodiscus Lebouri, a New Species of Agelacrinit.es, from 

 the Carboniferous Series of Northumberland." By W. P. Sladen, Esq. 



The genus Agelacrinites was unknown in the Carboniferous rocks 

 of Europe before the discovery of the fossil described in this paper; 

 and even in the Silurian and Devonian rocks species referred to this 

 group were exceedingly rare. The specimen now illustrated by the 

 author, which belongs to the subgenus Lepidodiscus, was found by 

 Prof. Lebour, and its study has thrown some new light on the structure 

 and affinities of the genus. One of the most striking facts concerning 

 it, now made out by the author, is that, like some recent forms of 

 Echinoidea, the species would seem to have been so constructed as to 

 permit of its plates overlapping, and thus to have been collapsible. 



9. "On the Ancient River- deposit of the Amazon." By C. Barring- 

 ton Brown, Esq., A.R.S.M., E.G.S. 



The author described a series of alluvial deposits, varying in thick- 

 ness from 10 to 160 feet, which have been cut through by the river, 

 and form a series of cliffs, giving rise to striking and characteristic 

 scenery. The succession of beds exposed in these cliffs was illustrated 

 by a number of sections, and it was shown that the strata in question 

 must have been deposited by river-action. It was then pointed out 

 that the river is performing two classes of work, namely, cutting away 

 the older sheets of alluvial matter, and depositing the materials derived 

 from them at a much lower level. The interesting phenomena of the 

 cutting of curves by the river, and the abandonment by the river of 

 parts of these curves, giving rise to the formation of lakes, was fully ex- 

 plained ; and in conclusion the author showed by a map what vast areas 

 in South America have thus been covered by these alluvial deposits. 



10. "The Glacial Deposits of Cromer." By Clement Reid, Esq. 

 In this paper the author described the beds shown in the cliffs be- 

 tween Weybourn and Happisburgh. The classification adopted was : — 



Sands and Gravels (Middle Glacial?). 



Bedded sand and marl. ) ^ , , , -n -u. 



Sedimentary Boulder-clay. \ Contorted Drlft - 



Fine Sands. 



2nd Till (unstratified Boulder-clay). 



Intermediate Beds (laminated marl, etc.). 



1st Till (unstratified Boulder-clay). 



Arctic Freshwater Bed. 



