76 i REPORT— 1900. 



to the reaular curves of beach formation were exhibited and attention drawn to 

 this interesting opportunity of witnessing the gradual formation and growth of a 

 beach. 



2. The Basal (Carhoniferous) Conglomerate of Ullswater and its Mode of 

 Origin. By R. D. OLDnAM, Geological Survey of India. 



On the western shore of Ullswater, near its lower end, a good section has 

 recently been exposed of the basal conglomerates, variously ascribed to Old Red or 

 lowermost Carboniferous age. This conglomerate has been considered as glacial in 

 its origin, but does not appear to the author to present any true glacial character- 

 istics. It contains angular and subangular blocks of all sizes, which are not 

 scattered indiscriminately, but are arranged with a distinct, though obscure, 

 banding. In the admixture of blocks of all -sizes and the absence of rounded 

 boulders, it ditl'ers Irom tbe known river deposits of temperate climes, and more 

 closely resembles the accumulations of debris which result from cloud-bursts than 

 any other form of deposit which can be observed in the British Isles at the present 

 day. The conglomerate cannot, however, be reasonably attrilmted to any such 

 local deposits ; its true analogue must be looked for in tbe dry regions of AVesteru 

 and Central Asia, where all rainfall rushes off the bare hills, producing an effect 

 very like that of a cloud-burst in our own climate, and causing a mixed mass of 

 water, silt, and s'ones to rush down the river channels, which are dry or carry only 

 a feeble stream in ordinary times. This mass of material is carried out from the 

 hills, and forms a deposit with a gently sloping surface extending for miles into 

 the open country. Carried along in this manner the rock fragments do not 

 undergo the rounding which they suffer in a more permanent torrent, and are 

 deposited, on the sudden subsidence of the Hood, in a mixed mass of fragments of 

 all sizes. The sections exposed along the roadside near the foot of Ullswater not 

 only exhibit a rude banding, due to the action of successive floods, but also show 

 patches of current-bedded, fine-grained, gravelly material, representing the action 

 of the feebler stream which continued after the passage of the dood. 



The conclusion drawn is that the conglomerate is a torrential deposit, formed 

 on dry land, near the foot of a range of hills, in a generally dry climate, varied by 

 seasonal or periodical bursts of rain. The red colour of the hne-grained material 

 suggests tropical or sub-tropical conditions, as the formation of red soils is at the 

 present day much more common in tropical than in temperate regions to such a 

 degree that it may almost be regarded as characteristic of a hot climate. 



3. Report on Photographs of Geological Interest.— See Repoi'ts, p. 350. 



4. Sections at the Alexandra Dock Extension, Hidl. By W. H. Crofts. 



These works situated immediately to the east of the Alexandra Dock, and 

 covering about sevenacres, necessitated the excavation of earth in situ to a depth 

 of about 20 feet over a great part of this area, the trenches being eight or twelve 

 feet deeper. The formations exhibited are glacial and post-glacial. 



There is evidence of a basin in chalk corresponding with tiie valley of the river 

 Hull, the top of the chalk on the east side of the valley being in places higher 

 than in the bed of the river. 



The glacial deposits reach from the sea on the east up the slope of the Wolds 

 on the west : these beds are depressed in the neighbourhood of Hull ; this depres- 

 sion is filled in with warp. 



The Humber warp to the extent of upwards of twelve feet covered the whole 

 area of the works ; below this over a greater part of this area a peat and clay bed 

 exists, varying from one inch to three feet in thickness, resting on glacial beds of 

 a varied character which borings show to be about sixt}^ feet thick, with angular 

 chalk and flint gravel between them and the solid chalk. 



