TIIK IM.IDCKNK SKKIKS 609 



be deposits formed in tin- estuary of that river. Other indications 

 of a large river (lowing from the south present themselves in the 

 ('miner (Forest) Beds, and Mr. C. Reid has carefully examined the 

 stones which compose the gravelly portion of the deposit. He 

 found the collection of pebbles to be such that if the river had 

 flowed from the south, west, or north, it must have brought a very 

 dillereiit assemblage. "It seems, therefore, that only from tin- 

 south-east and east could the stones be derived, and that the river 

 must have been very large is shown by the uniformity of the 

 comjiosit ion of the gravels at considerable distances apart ; if this 

 be the correct reading, the river can be no other than the llhine, a 

 view held by various writers ever since the Forest Bed was first 

 known."-'" 



With respect to the change in the climate, the fauna of the 

 Diestian Sand and Coralline Crag is that of a rather warm sea, and 

 the- mean annual temperature of the surrounding country must 

 have been decidedly higher than it is now in the same latitude. 

 The subsequent exclusion of the warm southerly current doubtless 

 caused a general diminution of temperature, but there were other 

 meteorologic and cosmic causes which operated in rendering the 

 climate more and more frigid, till at length in the Weybourn 

 Crag we find a fauna indicative of a climate somewhat colder 

 than that which at present prevails in Norfolk. This prepares us 

 for the great change which took place very soon after the formation 

 of that bed. 



In the Mediterranean area the closing scenes of Pliocene time 

 were connected with the subterranean disturbances which resulted 

 in the formation of the great volcanoes of Etna and Vesuvius and 

 the smaller vents of the Latian Hills. The earliest volcanic 

 eruptions appear to have been submarine, for the Astian and 

 Sicilian deposits of Sicily, Calabria, and Rome include inter- 

 stratified beds of volcanic ash and sand. It was not, however, till 

 the close of Pliocene time that the greatest discharges began, for 

 the building up of Etna and the elevation of the Pliocene deposits 

 to the levels at which they are now found, i.e. more than 3000 feet 

 above the sea, must have taken place in early Pleistocene time. 



REFERENCES 



1 G. F. Dollfus, "Essai sur 1'etage Aquitanien," Butt. Service Carte O(ol. 

 France (1909). 



2 S. Gardner, Oe.ol. Mag. for 1879, p. 152, and Monograph. Pal. Soc. on 

 the Eocene Flora, pp. 18, 19. 



3 C. Reid, Phil. Trans. R.S. vol. 201, B. p. 161 (1910). 



4 See Peugelly in Phil. Trans, vol. cliii. p. 1019 (1863), and Jukes- 

 Browne in Oeol. Mag. for 1909, p. 257. 



2R 



