Since the beginning of the century Carboniferous corals have been intensively studied throughout the world, and in this paper our resultant knowledge of their distribution and the sequence of faunas is outlined. The lower limit of the Carboniferous is taken to be at the base of the K zone of the Bristol sequence, and the upper limit at the base of the Russian Kungurian stage, in conformity with the principle of priority of nomenclature. The period is thus a long one including the Russian Artinskian, while the Permian is relatively short. Many recent writers, e.g. Dunbar (1940, 1942), adopting criteria other than priority of nomenclature, have extended the Permian downwards to incorporate greater or lesser amounts of the Carboniferous.

A large part of Central Sutherland is occupied by an injection complex in which rocks of the Moine Series are associated with much granitic and pegmatitic material. These migmatitic Moinian rocks have reached a higher grade of metamorphism than those which occur outside the injection complex. One feature characteristic of the high-grade migmatites is the presence of sillimanite in many of the pelitic and semi-pelitic rocks. Near the village of Kildonan, ten miles north-west of Helmsdale, sillimanite is not only abundant in the country rock, but occurs also in many pegmatitic and aplitic veins. The field and microscopic evidence shows that this mineral was formed as a result of metasomatic activity at a late stage in the history of the injection complex, when the general metamorphism was already on the wane. The sillimanite seems to have no direct connection with the conditions of regional metamorphism. It was formed under the influence of pegmatitic solutions. In view of the common use of this mineral as an index of the grade of regional metamorphism, it is of interest to describe the evidence on which the above conclusions are based.

In this magazine for January, 1938, there appeared a short note on the rate of sedimentation in the salt marshes of Scolt Head Island. The records then only covered two years. In a note in the Trans. Norfolk and Norwich Nat. Soc., 15, 1939, 41, some additional readings, covering four years, were published and analysed. This summer (June, 1947) I was able to measure the accretion again after a further interval of eight years, so that we now have rates and averages for two, four, and eight years. Unfortunately the line on Aster Marsh was partly destroyed during the war when it regrettably formed part of the target area for artillery fire.

The present paper is based on rnaterial partly from the collection of the Geological Survey of Great Britain and partly from a collection made by myself in May, 1947, at Kilmalaug Bay, North Trotternish, Skye. It is believed that the species of mollusca here reported form the first records from the Bathonian beds exposed there. Tate (1873) did not make any reference to this locality, although the area was marked as “Aird” on the map of the Islands of Skye and Raasay forming plate xi of Bryce's paper (1873), to which Tate's work was an appendix.