From November, 1930, till October, 1931, the Cambridge Expedition led by Dr. E. B. Worthington, carried out biological work on the Kenya and Uganda lakes. Owing to a grant from the Royal Society I was able to accompany the Expedition as geologist, with the object of studying the Pleistocene lake deposits and making collections of fossils from them.

So little is known about the geology of the Amazon that it seems worth while recording a few observations made during a recent journey up that river.

The westward extension of the South Wales Coalfield in Pembrokeshire is of complicated structure and the sequence is very imperfectly known. This is particularly true of the west of the county, where the coalfield has been very little worked for many years. In the eastern portion of the county, between Haverfordwest and Carmarthen Bay, the Coal Measures consist mainly of shales which have been correlated with the Lower Coal Series of the main part of the South Wales Coalfield and which are not higher than the Pulchra Zone.

The following notes were made while on an expedition with Mr. J. T. Cunningham (financed by the Trustees of the Percy Sladen Trust and the Royal Society) to the Island of Marajó in the mouth of the River Amazon. The object of the expedition was not geological so that it was not possible to carry out an extended survey of the district explored.

The name crinanite was given in 1911 by Sir John Flett to a suite of N.W. analcite-dolerite dykes occurring in a fairly extensive district in Argyllshire of which Loch Crinan is the centre. A description of the type is accompanied by an analysis and a photomicrograph of a characteristic example from the island of Jura. Writing a few months later of similar dykes in Colonsay, the same author gives a concise definition of the type—“The crinanites, then, are dark coloured, fine-grained, basic rocks consisting mainly of olivine, augite, and plagioclase felspar, with a considerable amount of analoite and zeolites.” A detailed description follows, in which the very perfect ophitic structure of the rocks is emphasized, and another excellent photomicrograph is shown of an example from Colonsay. In his original description Sir John Flett states that the crinanites “present some analogies to the teschenites in mineral composition; from the latter they are distinguished by their finer grain, their perfect ophitic structure, the scarcity of hornblende and biotite, and their occurrence as thin vertical parallel dykes”.