In the course of work carried out over several years since the War, the writer has observed certain widespread faunal bands in the Yoredale facies below the Millstone Grit of the Askrigg Block which deserve greater notice than they have htherto, if at all, received. These bands are of the type made famous by Garwood (1913) in his classical paper on the Lower Carboniferous faunal succession in North-West England, i.e., they are widespread, relatively thin horizons characterised by the great abundance of one, or sometimes two, species. The bands are as follows, in ascending order:-Giganfoplodtrctzrs-Band close to base of the Scar Limestone. Dibunophyllum-Band in basal part of the Four Fathoms-C. ScheUwdencllu-P?rsfirlu-Band of the Upper Stonesdale Limestone.
The first two of these have been traced by the writer over a wide area. In tracing the last, outcrops of which often lie high up the valleys of tributary streams far from any road, he has been greatly assisted by two research students of the Geology Department, University of Leeds, Dr. A. J, Rowell and Mr. J. E. Scanlon, who have been engaged on the arduous task of remapping the higher Carboniferous beds north of Wensleydale. Another student of the Department, Mr. D. Moore, who is studying the Yoredale Beds proper in Wensleydale, has ah0 given the writer some much appreciated help. H i s thanks are also due t o Professor K. C. Dunham for helpful discussion.
The task of tracing the full extent of these bands, particularly the DibuwphyUum-Band. is likely to be a long one, and as they have proved of some importance in correlation, it seems desirable to put on record a summary of the results so far obtained.
A.
B. Underset Limestone.
A. Gigunt~odirctzrs-Bad. (Fig. ). At the north-west corner of the Askrigg Block, east and south of Kirkby Stephen, the three-Recently, the Dibun@hyllum-Band has been located in Coal Gill, on the east side of Whernside, but it is definitely absent to the south-west incornbe Scar. This indicates that the southern limit of the Band, on plate xxxiv. should turn south-westwards toward the south-east corner. J.S.T., 6.7.55.