JET. 50.] RIVER DRIFT. 169 



J. Prestwich to H. Falconer. KENT TERRACE [undated]. 



MY DEAK FALCONER, Thanks for your friendly criticism. I 

 am, however, going to contest some of this. First, with regard 

 to river floods. 



There is no doubt but that the peculiar position of the 

 Siberian and North American rivers is one condition in the case, 

 but it is not the only one. There is not the same damming up 

 by ice, but still the floods in rivers such as the Kama and the 

 Volga, which flow from north to south, are also annual and 

 considerable. (See Pallas's Voyages, vol. vii. pp. 39, 210 ; vol. 

 i. p. 296.) 



So again in Lapland the rivers with a southern flow are sub- 

 ject to very considerable spring floods. Wrangell also speaks 

 of the floods in Southern Eussia as well as Murchison (his ' Eus- 

 sia '). They both mention that whole districts are flooded, and 

 the river valleys converted into great lakes. The majority of 

 these rivers have a southern flow. In more northern regions, 

 Eichardson and Simpson speak of the small local floods caused 

 by the melting of the snows, quite independent of the great 

 rivers. As I mentioned yesterday, I conceive the effect of a 

 severe winter must be to store up the rainfall and restrict its 

 delivery to a short period in the spring whence increased river 

 discharges and floods. 



Now with regard to the hippopotamus I give its tusk-teeth 

 legitimate use, but still I am not disposed to give up the cold 

 winter and its cold- climate associates. It is certainly found with 

 the reindeer, and I am inclined to believe that the gravel at 

 Hurley Bottom with the hippopotamus, and that at Taplow with 

 the musk-ox, are synchronous. I do not suppose the cold to 

 have been so extreme as at the Terrace Gravel period, and if 

 there were rapids in places on the old rivers at such parts, there 

 might have been open water all the winter. Otters are found 

 frequenting such rapids in the severe climate of North America, 

 and in rivers which at other places are frozen all the winter. 



R. A. C. Godwin- Austen to J. Prestwich. 



CHILWORTH, March 30 [1862]. 



DEAR PRESTWICH, Thursday evening last places me under 

 the obligation of saying how much I congratulate you on your 



