T. BELT ON THE STEPPES OF SOUTHERN RUSSIA. 861 



Discussion*. 



Mr. Drew said he should like to know by what marks Mr. Milne 

 knew the effects of the coast-ice. He thought that Mr. Belt's 

 theory was the same that that gentleman brought forward about 

 three years ago ; from the same data he had himself drawn very dif- 

 ferent conclusions. The supposed lacustrine deposits of Mr. Belt are 

 formed, he thinks, by the damming up of an, immense expanse of 

 water by an ice barrier. Mr. Drew thought it was really fluviatile, 

 and deposited by one or many rivers. The surface of the deposits 

 in the plain of the Danube follows the river- valley at a higher level 

 than the present bed ; and it was formed by material brought down 

 the slopes of the watershed. Mr. Drew illustrated his views by 

 reference to the Punjab and the plains of India. 



Prof. Prestwich agreed with Mr. Drew in his explanation of the 

 phenomena described by Mr. Belt, and said that, from what he knew 

 of Western Europe he believed that all such deposits as those described 

 by Mr. Belt may be explained by supposing them to be thrown 

 down in old river-valleys. In England these fluviatile beds rise to 

 100 or 150 feet, and in Erance still higher. In the flat country 

 dealt with by Mr. Belt the deposits would extend to a great distance. 



Mr. Milne had described his ice-scratches as at right angles to the 

 coast-line, but in most instances in inland striation the strise were 

 parallel to the coast-line. Had the rise of the land been very slow 

 the marks might have been obliterated ; but if the rise were rapid 

 the marks would not be effaced. 



Prof. Judd stated that he knew the beds referred to in the valley 

 of the Danube, and that the phenomena as worked out by the 

 native geologists gave great support to the explanation offered by 

 Mr. Drew and Prof. Prestwich. The most remarkable individuality 

 in the mud of each river-valley had been demonstrated. 



Mr. Hicks compared Mr. Belt's sections with those of similar 

 deposits in the east of England. 



Mr. \Yhitaker said he had been for some years engaged in the 

 detailed examination of comparatively small areas, in England, and 

 sometimes had not been able to make up his mind as to the age of 

 some of the Drift beds therein. There were glacial beds, postglacial 

 beds, and beds of which no one can say whether they are or are not 

 glacial. The difficulty thus experienced in interpreting a small area 

 which had been almost exhaustively examined, made him suspicious 

 of these broad generalizations from a few observed sections. 



Admiral Spratt remarked that Mr. Belt's sections reminded him 

 of many he had himself seen. The river-theory seemed to be plau- 

 sible and good ; but large rivers if ponded up make freshwater lakes. 

 The sands and muds are very soft and fine, and would float to a 

 great distance, like the Nile mud. Ealse-bedding shows river- 

 action in the lower beds or movement in shallow water. The shells 

 found by him in Bulgaria were perfectly lacustrine in character ; and 



* This discussion applies also to a paper by Prof. John Milne, read on the 

 same evening. See p. 930. 



