XXVII.—The Old Red Sandstone of Shetland. Part II. North-Western Area

Abstract

In a previous communication an account was given of the sedimentary series exposed along the eastern coast-line of the Shetlands from Rova Head to Sumburgh Head. Fossil evidence was adduced which enabled the position of these beds in the Old Red System to be fixed more definitely than had hitherto been the case; they were shown to be partly of Middle, partly of Upper Old Red Sandstone age, the base of the Rova Head Conglomerate being taken as the dividing line. Since the publication of that paper additional fossils have to be recorded. Examination of the numerous specimens of the Microbrachius from the fish-beds of Shetland fails to reveal any specific distinction between that form and Microbrachius dicki Traq. occurring in the John o' Groat's Sandstone Group, and the Eday Sandstones; it is therefore an important addition to the chain of evidence linking up the Shetland horizon with those of Orkney and the Mainland. An additional record of little stratigraphical value is that of Coccosteus (sp. indet.), a single plate of which was found by Professor W. H. Lang at a horizon slightly below the fish-bed at Shingly Geo, Dunrossness.