226 Reports and Proceedings. 



The author described th.e Cerro de Sal, or Salt Mountain of St. 

 Domingo, which extends about three leagues in length, and consists, 

 according to the author, of rocks " of the Eed Sandstone class," and 

 where the chief visible deposits of salt occur are principally gypsum- 

 echists, sometimes very argillaceous. The salt is generally surrounded 

 by an ash-like mass, consisting of gypsum and clay. The author 

 compared the gypsum beds with those of the Keuper. The beds are 

 thrown into a perpendicular position, and the same change is ob- 

 servable for miles in the Savanas. An immense body of salt, 250- 

 300 feet broad, is exposed upon the north side of the mountain. 

 The salt is very white and pure, and might easily be conveyed to the 

 port of Barahona, about eighteen miles distant. 



Discussion. — Sir R. I. Murchisoii had been at a loss to understand how such beds 

 of salt could coexist with shells of recent species in St. Domingo. The question 

 seemed, however, to have been solved by the geological survey of many of the West 

 Indian islands, which had determined that all these deposits were of Miocene age. 

 In the majority of the islands there were no rocks so old as the Cretaceous, and he 

 therefore suspected that there was an error on the part of the author in regarding 

 the beds of St. Domingo as belongmg to the Trias. 



Prof. Eamsay thought it was more remarkable that any salt-deposits of the New 

 Eed Sandstone should exist than that there should be so many of Miocene age. 

 There was not much probability of great salt-deposits of more recent date, as there 

 had hardly been sufficient time for their formation, though in the Great Salt Lake 

 and elsewhere such deposits were now forming. The reason why such old deposits of 

 salts had been preserved appeared to be that the salt had been hermetically sealed 

 up in impermeable marl as soon as the part of the salt which lay near the outcrop of 

 the beds had been dissolved away. 



Mr. Etheridge was satisfied that the shells from St. Domingo which came with the 

 Bait are of Miocene age. In other West India islands gypsum of Miocene age 

 occurred, and pseudomorphs of salt. He recommended Mr. Sawkins's work on the 

 Geology of the West Indies to the attention of geologists. 



4. " A description of the ' Broads' of East Norfolk, showing their 

 origin, position, and formation in the Valleys of the Eivers Bure, 

 Yare, and Waveney." By E. B. Grantham, Esq. C.E., F.G.S. 



The author described the general characters of the " Broads," or 

 shallow lakes of East Norfolk, and indicated their connection with 

 the river valleys. He regarded them as the last traces of great 

 estuaries, now cut off from the influence of the sea by upheaval. 



Discussion. — Mr. J. Gwyn Jeffreys suggested a zoological as well as a geological 

 examination of these lakes. If of marine origin, possibly some marine forms might 

 be found still existing in them, as had been discovered to be the case in some of the 

 lakes of Sweden. 



Mr. Searles Wood, Jun., agreed that these broads were of later date than the ex- 

 cavation of the valleys. He cited Mr Prestwich's account of the boring at Yarmouth, 

 which showed a large amount of silting up of the valley. 



Mr. Prestwich inquired whether the amount of silt at the bottom of these broads 

 had been ascertained, and whether any estuarine shells had been found in the beds 

 at the bottom. 



Professor Ramsay suggested tha tthe broads might be relics of the old valleys of 

 the time when the Thames and other rivers of the east of England united with the 

 Rhine and other continental rivers to flow into the Northern Ocean. 



5. " On a peculiar instance of Intraglacial Erosion near Norwich." 

 By Searles Wuod, Jun., Esq., F.G.S., and F. W. Harmer, Esq. 



The authors described the general structure of the valley of the 

 Yare, near Norwich, in which the fundamental Chalk-rock is covered 

 by the following drift-beds : — 1, the Chillesford sand and clay ; 2, 

 pebbly sands and pebble-beds; 3, the equivalent of the contorted 



