Geological Society of London. 135 



established ; and he proposed the following classification of the 

 Bagshot Beds of the London Basin : — 



Old Eeading. New Reading. 



1. Upper Bag-shot vSands = 1. Marine -estuarine Series. 



2. Middle Bag-shot Sands and Clays ^ _ „ freshwater Series 

 . Lower Bagshot Sands j 



(2).— February 9, 1887.— Prof. J. W. Judd, F.R.S., President, in 

 the Chair. — The following communications were read : — 



1. " Evidence of Glacial Action in the Carboniferous and Hawlces- 

 bury Series, New South Wales." By T. W. Edgworth David, Esq., 

 F.G.S. 



After giving a tabular statement of the sequence of rocks connected 

 with the coal-bearing beds in New South Wales, the author passed 

 in review the notices by previous observers of glacial action in the 

 Carboniferous beds of that country, terminating with the discovery 

 by Mr. E. D. Oldham of polished and striated boulders in fossiliferous 

 marine beds of Carboniferous age at Bi-anxton. The author had since 

 found another extensive deposit of similar beds at Grass-tree near 

 Musclebrook, 28 miles N.W. of Branxton, and described the section 

 there exposed in a railway-cutting. A fine calcareous sandy shale, 

 reddish to greenish-brown in colour, was crowded with round and 

 subangular fragments of rock, from pebbles no larger than marbles 

 xip to a third of a ton in weight. The surfaces of these fragments 

 were in many cases ground and scattered. The parent-rock of some 

 of the boulders was 30 miles distant. 



The evidence of ice-action in the Triassic Hawkesbury series was 

 also described. This evidence was twofold, and consisted of the 

 disrupted angular fragments of shale first observed by Mr. Wilkin- 

 son, and of contemporaneously contorted current-bedding, of which 

 no account had previously been published. The contortions were 

 represented on a diagram, and attributed to a lateral thrust such as 

 would be produced by the grounding of floating-ice. 



The discovery by Mr. Wilkinson of polished and striated boulders 

 in some gold-bearing conglomerates, believed to be of Siluro-Devo- 

 nian age, was also noticed. 



2. " The Terraces of Eotomahana, New Zealand." By Josiah 

 Martin, Esq., F.G.S. 



The author, after deploring the recent calamity, proceeded to de- 

 scribe the White Terrace. Its origin, the Terata Geyser, was situated 

 in a crater-like escarpment near the centre of a conical hill of steam- 

 ing and partially decomposed felspathic tufi" on the south-east side 

 of the warm lake, Rotomahana. The Terrace was divided into : — 



1. The Upper Terrace, with its long horizontal lines of cups, 

 steaming and overflowing with hot water. 



2. The Middle Terrace, with its massive steps and shaggy fringes, 

 without basins or receptacles for the overflow. 



'6. The Lower Plateau, a series of shallow basins and wide, level 

 platforms. 



The great cauldron and the action of the Geyser were described 



