140 Reports and Proceedings — Geological Society of London. 



to the neighbourhood of Barnstaple. Since that paper was read, 

 the author has obtained much additional evidence bearing on the 

 succession, which is given in the present paper so far as the position 

 and nge of the Morte Slates in the Ilfracombe area are concerned. 



The author describes the lithological characters and fossil contents 

 of the Morte Slates, and their relationship to the Pickwell Down 

 Sandstones and Ilfracombe Beds, treating of the development of the 

 rocks in four areas, viz. : Morthoe and Woolacombe to Bittadon ; 

 Eockham Bay, Bull Point, Lee, and Slade ; Mullacott, Shelfin, and 

 Ilfracombe; and Woolscott Barton, Smithson, and Berry Down. 

 The great abundance of detrital mica in the Ilfracombe Beds and 

 Pickwell Down group, and its almost entire absence from the 

 Morte Slates, are noticed. The faulted junction of the Pickwell Down 

 Sandstones and Morte Slates is described, and it is held that the 

 faulting has not thrust older beds over newer, as maintained by 

 Jukes, but that the order of succession is the original one, whereas 

 the overthrust fault separates the Morte Slates from the now under- 

 laying though newer Ilfracombe Beds, which often dip away from 

 the Morte Slates, while different members of the Ilfracombe series 

 abut against the Morte Slates, so that the latter form a complex 

 group of older rocks bounded on either side by newer strata. The 

 author states that the fossils found in the Morte Slates belong to 

 several horizons, some probably as low in position as the base of 

 the Silurian (Upper Silurian of the Geological Surveyors), while 

 none of the beds of the series appear to be newer than the older 

 Devonian. In some places newer rocks may occur amongst them 

 as the result of faulting or unconformity, but not in order of 

 succession. 



A description of the species found in the Slates is appended to 

 the paper. 



2. " Evidences of Glacial Action in Australia in Permo-Carbon- 

 iferons Time." By Prof. T. W. Edgeworth David, B.A., F.G.S. 



The author, after summarizing the work of previous observers, 

 gives an account, of recent observations made hy himself. 



In Hallett's Cove, near Adelaide, the pre-Cambrian rocks are 

 strongly glaciated, stria? being seen when the overlying glacial beds 

 are removed, as sharply cut as though caused by recent glacial 

 action, and trending nearly north and south, the ice having come 

 from the south. The overlying glacial beds are in places fairly 

 stratified, while parts contain abundance of well-striated boulders : 

 these beds are from 23 to over 100 feet thick. Proofs were obtained 

 that in this case the glaciation occurred in an age intermediate 

 between Miocene and pre-Cambrian, and probably did not antedate 

 the close of the Palaeozoic period. 



In Wild Duck Creek, near Heathcote, Lower Silurian (Ordovician) 

 beds exhibit strongly-grooved, polished surfaces, the grooves being 

 from S. 5° E. to N. 5° W., the ice probably having come from the 

 south. They are succeeded b}' Permo-Carbonif'erous glacial beds, 

 consisting chiefly of mudstones with well-glaciated boulders. 



At Bacchus Marsh, Ordovician beds are also well striated and 



