Some additional data are given regarding the “newer” intrusions of an area of which the main petrological features have been described elsewhere. The intrusions are:— (1) Aplites, pegmatites, quartz-veins, granodiorite porphyries, and biotite-granodiorites in or around the Newer Diorite. (2) A “porphyry” contaminated by cordieritic hornfels and having “clouded ” plagioclase “phenocrysts ”. Evidence is given that the “phenocrysts” have xenocrystic cores. (3) Quartz-felsites with cordierite, andalusite, and garnet, and granodiorite-porphyries, lying between the Newer Diorite and its roof of Ben Lawers Schist. The granodiorite-porphyries post-date the Diorite but the age of the quartz-felsites is uncertain. Contamination, and mechanical and chemical alteration, of the quartz-felsites are recorded. (4) Newer quartz-felspar-porphyries and lamprophyres, not obviously associated with the Newer Diorite.

The structure of the fronto-ethmoid shield of Osteolepis macrolepidotus Ag. is described fully for the first time, and the homology of the dermal bones is discussed. The most interesting feature is the recognition of the existence of a sensory-canal bone bearing teeth in the position of the premaxillary of Tetrapods, with which it is shown to be homologous; the nomenclature of the equivalent bones suggested by Säve-Söderbergh is discussed and revised.

The presence of a continuous cosmine sheet overlying several bones is emphasized, and the problem of growth of such a combination is brought out. It is shown that the problem can be solved by extensive resorption and redeposition of cosmine, and this hitherto unnoticed change is demonstrated in a number ofOsteolepids and in some Dipnoi. The results of the resorption are to free the bones of the head from the cosmine, and thus to expose the top of the true bone ; the new characters are those usually associated with different genera, usually placed in distinct families.

Finally it is noted that the resorption involves a general chemical change affecting cosmine all over the body, which it is suggested may be due to the release of an internal secretion, the whole process of resorption and redeposition of cosmine being cyclic and almost certainly seasonal, growth being therefore a seasonal change.

A pegmatite cutting granodiorite contains abundant xenoliths which are in various stages of assimilation. Assimilation involved the conversion by the process of “reciprocal reaction” of the minerals of the xenoliths into species which were in equilibrium under the prevailing magmatic conditions, and the subsequent “mechanical disintegration” of the xenoliths with the strewing of their minerals in the pegmatite. Solution of xenolithic material was not important, probably only affecting potash-felspar. The fact that the active magma was a pegmatite suggests that high temperatures were not available, and its assimilating power must be attributed to its large volatile content. The xenoliths were probably derived from the walls of the pegmatite vein both in the granodiorite and in the country-rocks.

Nearly thirty years ago Penck and Brückner published Die Alpen im Eiszeitalter, which has moulded the views of European glacialists over since. It is the basic authority for the theory that there were four glaciations—the familiar Günz, Mindel, Riss, and Würm—separated by three warm interglacial periods. This theory has been further elaborated to such an extent that Zeuner (1935) lists some eight or nine glacial phases with a corresponding number of intervening warm phases.