A stay at Sidmouth during the past summer (supplemented by a second visit to the county in the Christmas holidays) has afforded me the long-wished-for opportunity of forming a personal acquaintance with the Red-Rock series of the Devon region, rocks which were described many years ago by Mr. Godwin-Austen* under the name of New Red Sandstone, and have been more fully described since by Mr. Ussher†. The paper by the latter author is of great value, as it is a very mine of facts and observations. In working along the coast-sections, however, I saw reasons for doubting the correctness of including the whole series in the Trias, and as I went on and compared what I observed with the results of the work of former years‡ in the Dyas and Trias of Germany and of the northern and midland counties of England, I was forced to the conclusion that in the Devon region we have those two systems represented. I propose to lay before the Society in this paper an account of the observations which I have made, and to state the conclusions which (on comparative grounds) I have drawn from them. Sidmouth(East). (1) The escarpment of the Sid, for some 300 yards from its mouth, consists of about 50 feet of thick-bedded coarse sandstones, of a prevalent peppery-grey colour, in fresh sections, the general red colour of their weathered surfaces being due to rain-wash from above and subsequent infiltration. They exhibit magnificent current-bedding, such as we commonly meet with in