V.— The Outlier of Carboniferous Rocks at Bridge of Awe, Argyllshire

Abstract

During an inspection of sections exposed in the recent road-widening operations between Taynuilt and Loch Awe, an opportunity was taken to re-examine the small outlier of Carboniferous rocks near the Bridge of Awe at the west end of the Pass of Brander (Geological Survey One-inch Map, Sheet 45). It was hoped also that the investigation would yield some points of comparison with the Carboniferous strata of Inninmore on the Sound of Mull (1). The Bridge of Awe sediments seem to have been first noticed by Macculloch in 1817 (2). The red colour of the beds and the fact that they outcrop in the midst of lavas of Lower Old Red Sandstone age led observers to regard them as belonging to the same formation. They were assigned this age in the ‘Summary of Progress of the Geological Survey for 1897’ (3), but in the following year Mr. D. Tait obtained from shales a little north of Bridge of Awe a few fragmentary plant remains which definitely proved the sediments to be Carboniferous (4). The accompanying sketch-map indicates the approximate limits of the outlier. It is largely concealed beneath alluvial deposits and the only sections are those exposed on the banks of the River Awe. The actual junction with the underlying lavas can be seen on the right bank below the bridge and at two localities on the left bank above it. The exposures above the bridge, however, can only be properly examined when the river is low. The writers were fortunate This 250-word extract was created in the absence of an abstract The authors desire to acknowledge the help given by Professor J. W. Walton and Dr. R. Crookall in the examination of material and the assistance of Mr. W. Manson in the field.