ABOUT twelve years ago Dr. R. H. Rastall and Mr. J. Romanes published an account of the Boulders of the Cambridge Drift. In this paper a list was given of the rock-types recognized at that time in the gravels of the Travellers' Rest Pit, situated about a mile north-west of the town of Cambridge on the Huntingdon Road. Since that time Professor Marr has paid much attention to this pit, among others, with special reference to the Palæolithic implements there found. He has embodied his results in two important papers. In the course of this work Professor Marr collected a number of interesting erratics, and the same pit has also been investigated by many geologists connected with the University, both members of the Sedgwick Club and others. During the last ten years, though the North Pit has been abandoned, the South Pit has been very actively worked for gravel, and has been greatly increased in size. In consequence of this a large amount of additional material has been collected, including many new types, while some of the older specimens, whose origin had been left indeterminate by Rastall and Romanes, have been now identified. Hence it is felt that the time has now arrived when these more recent results should be put on record.