It is believed that the “ beef ” in the shales-with-“ beef ” resulted from the leaching of the CaCO3 of a fine porous marl by a groundwater solution, and its subsequent redeposition. The initial redeposition was about the grains of calcite along bedding planes or similar divisional openings, and, as more material was added by the solutions moving to these planes, each original grain developed into a fibre in the layer of “ beef ”. Growth was from both sides, but took place faster on the upper side because the dominant movement of the water was downward. Growth stopped due to the exhaustion of the supply of CaCO3 in the marl or CO2 in the solution. The thin paper-shales between the layers of “ beef ” may represent the concentration of the original clay of the marl. This explanation of the origin of the “ beef ” would probably apply to other fibrous deposits of calcite, also.

As early as 1875, Michel-Lévy made what is believed to be the first reference to that intergrowth of plagioclase and vermicular quartz which Sederholm later (1897) named “myrmekite”. In spite of its early recognition and characteristic appearance, however, there was for long no general agreement as to the geological significance or even the exact nature of the intergrowth. It appeared to be confined to the granitoid plutonic and metamorphic rocks, Becke (1913) having categorically stated that it does not occur in “eigentlich vulcanischen Gesteine”, so that it was with interest that the author recently (1932) recorded its occurrence in an Upper Devonian meta-toscanite from Marysville, Victoria. This does not conflict with Becke's statement, since the rock in question has suffered metamorphism by an intrusion of granodiorite, and is therefore not an “eigentlich“ volcanic rock. Nevertheless the mode of occurrence is unique, and the history of the toscanite has been elucidated with sufficient detail to allow one to infer with some accuracy the conditions under which the myrmekite was produced. In the following account, the myrmekite, biotite-quartz-symplektite, and biotite-dactylite in the subjacent granodiorite and neighbouring adamellite bodies, as well as the myrmekite in the meta-toscanite, are described.

In the Abstracts of the Proceedings of the Geological Society of London, No. 1254, of 16th December, 1932, Mr. L. R. Cox described certain siliceous boulders, and their Lower Tertiary fauna, collected for the most part at Hudi, north of the Atbara, by Mr. G. V. Colchester and others. As Mr. Grabham pointed out, the implications that the nature of the boulders and their fauna involve are of supreme importance to the geology of this part of the Nile Basin and, for that matter, of Africa.

The following article is an account of an area of some 1,000 square miles in the Anglo-Egyptian Sudan, crossed by latitude 13·30 N. and longitude 35·00 E. which was surveyed on the 1/50,000 scale during the years 1930 to 1932 by W. H. Tyler, who has published a brief note on the general geology (13).1 W. H. Wilcockson is responsible for the petrology.

The object of the present paper is to describe certain metamorphic rocks which occur in the eastern cordillera of the Ecuadorian Andes, immediately to the east of the interandine basin of Cuenca (Fig. 1). The latter region contains a series of late Tertiary volcanic breccias, followed by hard white shales which are overlain in their turn, and possibly in part replaced laterally by the massive, white, saccharoidal and tuffaceous sandstones of Azogues, in the composition of which rearranged volcanic ash and detritus play a large part (Fig. 2). These beds, originally described collectively as the Azogues Sandstone by Wolf (1),1 were considered to be of Wealden age upon the evidence of a meagre lacustrine fauna discovered by the same author, and subsequently described by Dr. Geinitz, of Dresden, which were found in the more shaly sandstones of the group. A more extensive collection of fossils made by the present writers from the same beds and localities was submitted to Dr. W. B. Marshall, of the United States National Museum, who reports that it consists largely of new genera and species, and that the age cannot be later than the Pliocene, and it may be earlier (2). These beds are thrown generally into a series of relatively gentle folds, having a north-south trend, but occasionally they are found in a more highly disturbed condition as, for example, on the Biblian-Azogues road, where they are sometimes seen to be vertical. The strike of the folding shows that it is a product of pressure from the same direction as that which accompanied the main Andean uplift.

During the month of August, 1931, the writer visited the scene of the extensive works at St. Albans, undertaken by the Verulamium Excavation Committee under the directorship of Dr. R. E. Mortimer Wheeler, on the sites of the Roman cities of Verulamium.