354 SECTIONAL TRANSACTIONS.— C. 



several thousands of feet of red beds accumulated there. In Nottinghamshire 

 the sea extended from Germany up to the Pennines which were rising, at 

 intervals, during the period. On the coast, breccias, dolomite, and red marl 

 formed according to the varying depth of the sea, and on the shore dune- 

 sands were spread. Gypsum-beds were evidently deposited from the sea, 

 which twice dried up, but the mass of the mineral offers a problem. The 

 Midlands rocksalt is of lacustrine origin. 



The dolomitic sandstone of Mansfield represents a sandbank formed 

 opposite the mouth of a river. 



Mr. F. W. Shotton. — The Aeolian deposition of the Lower Bunter of 

 Worcestershire and East Shropshire. 



The areas of Lower Bunter outcrop examined, over a number of years by 

 the Lapworth Club of Birmingham University, comprise three north-south 

 strips separated from each other by strike faulting, and lying approximately 

 in the triangle with Oakengates, Bewdley and Stourbridge at its corners. 

 Every exposure accessible in the area was examined, and dip readings were 

 taken, and sketches made of each unit of false-bedding. These readings, 

 over a thousand in all, were examined statistically. A considerable number 

 of rock specimens, including a regularly spaced series over 500 feet of a 

 core, were examined for grain-size variation. The main conclusions reached 

 were : 



(i) Every portion of the Lower Bunter is false-bedded. 



(2) Wind deposition is responsible for all the deposit. 



(3) The false-bedding is consistent with a constant wind direction 

 combined with an increasing bulk of sand. 



(4) The wind blew consistently from the east, from the direction of the 

 Mercian Highlands. 



(5) The sand is ' millet seed ' down to a diameter of about o • i8 mm. 



(6) The sand is amazingly well graded, not only in individual samples, 

 but in the deposit as a whole. Apart from pebbles which may occur 

 in the bottom few inches of the deposit, no particles exceeded i • i mm., 

 and there are no clay or silt bands. The median diameter of particle 

 for the whole deposit is 0-20 mm., and 90 per cent, lies between the 

 ranges of o • 50 and 010 mm. 



Mr. A. N. Thomas. — The Triassic rocks of north-west Somerset. 



The area in which the Triassic rocks are to be described lies between 

 Porlock and Williton. The lowest deposits of the New Red Sandstone in 

 the corridor between the Quantocks and the Brendons are usually classed 

 as Permian. West of Williton, they are overlapped by Bunter Pebble Beds 

 and finally by Keuper Sandstone and Keuper Marl, which in Dunster 

 Park rests directly on Devonian. The sub-Triassic surface is highly 

 irregular and the earliest deposits fill in isolated valleys and depressions, 

 their outcrops subsequently connected by the more widespread later 

 deposits. In Bunter times the area between Williton and Minehead formed 

 part of the main south-west basin in which were deposited conglomerates 

 formed of pebbles of Carboniferous limestone and Devonian Grit. 



The Vale of Porlock formed a separate basin, which was filled in by 

 Bajada breccias of very local derivation. The pebble composition of the 

 breccias shows a striking correlation with the Devonian rocks of the imme- 

 diate hinterland. These breccias were deposited in fans that, originally 

 isolated, finally coalesced and were covered by the waters of the Keuper Lake. 



