For the last few years many geologists have been unable to keep in touch with the literature of their subject, partly owing to pre-occupation with war work of various kinds and partly owing to the spasmodic arrival in this country of non-British periodicals. The following short bibliographical notes on one limited branch of geological research have been put together in the hope that they may be of use to those who are now returning to their normal avocations, by affording them some idea of what has been done in America in the way of petrological investigation during the last few years. The list makes no pretence at completeness, since the compiler is himself suffering from the difficulties mentioned above, and the abstracts have purposely been made as short as possible, giving merely the barest indication of the contents of each paper, as a guide to readers who may desire to select what is of special interest to them. If the idea meets with approval it is hoped to publish from time to time similar compilations on other branches of geology.