672 REPORT— 1888. 



Sub-Section C. 



1. The Watcomle Terra-Cotta Clay. By W. A. E. UssHER, F.G.S. 

 [Communicated by permission of the Director-General of the Geological Survey.] 



The Lower Trias Conglomerates at "Watcombe rest upon about 20 feet of sand- 

 stones made up of comminuted slate : these are succeeded by red marly and shaly 

 clay, cut off by fault at the south boundary of "Watcombe Combe, but reappearing 

 on the south side of the intervening faulted mass of conglomerate, in Petitor 

 Combe, where the beds of marl and clay are apparently at a lower horizon than 

 those of Watcombe, and tbey are interstratified ^^^th sandstones made up of com- 

 minuted slate. They rest on broken limestone, through which the red mud has 

 permeated. The junction-beds are in places local masses of breccia. 



The series above described is visible nowhere else on the coast, but has been 

 traced inland by the author to Kingskerswell and Torre. Its character 

 changes in this westerly extension, the sandstones often assuming the aspect 

 of a line breccia, and the clay becoming an indurated mudstone, brecciated in places. 

 About 40 feet of these beds are exposed in a large pit near the Torquay Cemetery, 

 where they are faulted agains: Devonian slates. Beds on this horizon, apparently, 

 consisting of clay and loam with gravelly detritus dispersed throughout, occupy 

 the slopes of the Daccombe Valley, near Kingskerswell on the east. In the Wef- 

 lington Co.'s (Thomas) pits a small mass of porpbyrite occurs in the sands and 

 loams which there constitute the upper part of this series. Towards Torre Station the 

 AVatcombe clays pass under breccia and conglomerate ; red marl and shaly clay 

 occur in the railway cutting. 



To the north of Kingskerswell the Watcombe clays do not appear to have ex- 

 tended far, as the conglomerate and breccia of the overlying beds rest on the 

 Devonian rocks bordering the estuary of the Teign. 



To the south and west of Torre and in the Paignton area no lithological equiva- 

 lent to the "Watcombe clays has been observed. But it is quite possible that con- 

 temporaneous deposition took place in these districts ; the components of the Lower 

 Trias exhibiting such frequent local variation that no great faith can be placed in 

 the maintenance of lithological distinction on definite horizons. 



The Watcombe clays, however, may be the oldest Triassic rock in South Devon, 

 and may have attained a much greater development to the eastward of the present 

 coast, although restricted within narrow limits in their westerly extension. 



The author concluded by adhering to the classification he had propounded for 

 the Triassic rocks of the south-western counties, and saw no reason to alter the 

 position therein assigned to the Watcombe clay.' 



2. Second Report on the ' Manure ' Gravels of TFe.i/orcZ. 

 See Reports, p. 133. 



3. Beds exposed in the Southampton Xeir Dock Excavation. 

 By T. W. Shore, F.G.S., F.G.S. 



The beds described in this paper have been exposed during the progress of an 

 excavation of eighteen acres for the purposes of a deep-water dock at Southampton. 

 The site of the excavation is at the junction of the tidal rivers Itchen and Test in 

 the Southampton water, the area excavated having previously been covered with 

 tidal water to a depth varying from 12 to 17 feet. The excavation has brought to 

 light the succession of beds to a depth varying from 3G to 42 feet below the 

 surface of the alluvium over this area. From 5 to 17 feet of tidal alluvium lay at 



' In a paper by Mr. Appleton 'On Economic Geology of Devon ' (Tran.t. Dev. 

 Assoc, for 1875, p. 2il), an analysis of the Watcombe clay, by Dr. Percy, is given. 



