' H. H. Howorth — Traces of a Qrcat Pod-Glacial Flood. 437 



during a long-continued fluviatile denudation — because such a suc- 

 cessive and long-continued transport could not have failed to grind 

 the smaller pebbles into sand, and to reduce the angular flints into 

 all stages of wear, connecting them with the pebbles themselves " 

 (Journ, Geol. Soc. vol. xxvii. pp. 9, 10). This is assuredly most 

 sound, and it seems to me to make the fluviatile theory iinpossible. 

 Kiver gravels are so common, and can be studied so easily, that it 

 needs only a very elementary survey to predicate of them that they 

 invariably consist of rounded and rubbed pebbles, the result of tlie 

 grinding action of the stones against one another iu the narrow 

 troughs in which the river flows. 



In addition to the angular pebbles, the gravel also contains in 

 many places, as is well known, masses of greywether sandstone. 

 The evidence furnished by these is absolutely at one with that 

 of the angular flints. They have the same angular edges, which 

 preclude their having been rubbed and scoured by river action. 

 If we turn from the more solid contents of the gravel to the matrix 

 in which they are imbedded, we have the same story to tell. The 

 pebbles in river gravels for the most part are washed clean, or at all 

 events are not imbedded in a loose matrix of loamy sand such as is 

 that which characterizes the angular gravel of the South of England, 

 and characterizes it in a very homogeneous way over a very v/ide 

 extent of country. Again, in the deposits which are unmistakably 

 fluviatile, the beds are arranged in stratified fashion, and there is to be 

 seen evidence of a long-continued and secular deposition of materials. 

 Here, on the contrary, evidences of stratification are almost entirely 

 wanting, the arrangement of the materials of the gravel is often 

 most irregular and tumultuous, a very good specimen of this 

 arrangement being the one to be seen in the well-known Sugar Loaf 

 Chine west of Poole Harbour. In many places, again, we have 

 streaks and slabs of sand of more or less lenticular shape intercalated 

 among the gravel. In these features surely we have every sign that 

 the gravel was anything but fluviatile. As Mr. Belt says of similar 

 deposits somewhat further north than the area we are considering : 

 " The irregular and fitful stratification, the short lenticular patches 

 of sand, the mixture of sand throughout the gravel, the large stones 

 at the base, the great proportion of broken flints with slightly worn 

 angles, and the occasional oblique lamination, are all opposed to the 

 theory that the deposit is the result of successive layers of materials 

 brought down by a river at different times " (Quart. Journ. of 

 Science, 2nd series, vol. viii. p. 329). 



Let us now turn to another feature of these gravels. If they had 

 been deposited in a river channel, we should surely have found that 

 channel where we can examine it marked by the usual features of 

 fluviatile beds, scoured into a tolerably uniform trough, but here, as 

 may be seen in the magnificent sections exposed along the English 

 Channel, the gravel lies on the torn and ragged surface of the 

 underlying soft strata, which is torn and scooped in such a violent 

 and irregular manner with projecting beaks, etc., that it is incredible 

 how any river action could have first formed it. 



