A contribution by Messrs. Horwood & Wade to the Geological Magazine for November, 1909, calls attention (p. 505) to certain papers by me on the relation between the gneisses and schists and the later granites of Southern Nigeria.

Capping a small patch of London Clay on the highest part of Bostall Common (234 O.D.), there is a ‘drift’ that presents peculiarities identical with part of the gravel on Shooters Hill (2 miles distant) at 424 O.D.

On the occasion of a recent visit to the quarry in the Great Oolite at Milton-under-Wychwood, which has become known amongst geologists as —Groves' Quarry, Milton”, Mr. E. T. Paris, F.C.S., and I were disappointed to find that no quarrying operations were in progress and that apparently they had ceased for good.

The central position of Leicestershire gives it not only a peculiar relationship in regard to river-drainage, streams radiating from its plateau-frontier on the one hand to the north, flowing into the Humber, and on the other to the south into the Bristol Channel, separated alone by a now comparatively insignificant divide in the neighbourhood of Lutterworth. Also the very fact that this divide is given, by the otherwise lowland character of the tract to the north and south, a barrier-like aspect, renders it highly probable that the flora and fauna in this basin-like area is more or less homogeneous. That it has been uniform in character, no doubt from pre-Glacial times, when doubtless the existing drainage systems (though probably still more ancient fundamentally) received their most recent stamp, having been little modified (except in depth or width) during Glacial or later times. For this purpose we must needs summarize all that is known as to the occurrence of plants or land and fresh water Mollusca in post-Pleistocene alluvial deposits.

The losses of their constituents during the decompositions of the rocks.— As shown in this paper the analyses of the rocks and of their decomposition-products do not indicate the extent of the degradation which has taken place. To ascertain this it is necessary to re-calculate the analytical figures so that their proportions are comparable to those of one of the constituents which is assumed to have remained unchanged. The structures of the Surinam and the British Gruiana bauxitic laterite show clearly that, contrary to what is not unfrequently assumed, alumina cannot be regarded as a static component in rocks and their decomposition-products. It is evidently under condition of lateritization capable of entering into solution, transference from place to place, and redeposition in the form of alumina hydrate where conditions are favourable. The constituent which appears to be the most stable under conditions of weathering is titanium oxide, especially that present as ilmenite. But unfortunately as a rule it is present in such low proportions in rocks and in their residuary products that, when taken as the static constituent, errors in analysis of low value are productive of variations of wide extent in the results calculated on them.

In this communication it is proposed to briefly note the divisions which have been proposed for the Lower Carboniferous Rocks of Great Britain and Belgium; to discuss their validity in the light of the important additions that have been made to our knowledge during the last few years; and to suggest a new classification which, while expressing the physical and faunal changes which characterized that particular time interval, shall be generally applicable and at the same time do justice to the workers who have contributed most largely to our knowledge.