12 THE FINER FLOOD SEDIMENT 



many soft and friable or decomposod rocks, and 

 valleys surcharged with beds of fltiviatile Loess de- 

 posited on their flanks during the Glacial period, then 

 the waters must have become heavily laden with a 

 mass of fine sediment. So long as the waters were kept 

 in motion, little of this sediment would fall, but 

 during intervals of rest, and at the high tide of the 

 submergence, it would, especially in salt water, fall 

 rapidly, and soon acquire large dimensions, and so 

 cover the country as with a mantle. As the land rose 

 from beneath the waters, divergent currents scoured 

 the narrower passes and contracted channels, and 

 carried down much of the subsided ooze and re- 

 deposited it at lower levels ; whilst where the 

 currents were slighter, or the sediment had fallen 

 in sheltered positions or on tablelands, the deposit 

 would suffer but little denudation. As with the 

 other forms of the Bubble-drift, this sediment contains 

 the remains of land animals and land shells, but in 

 smaller proportion than the river sediments. It is a 

 deposit which covers large tracts of Central Europe, 

 forming a high-level Loess, and passing, when it is 

 more argillaceous, into the common brick earths. In 

 the Mediterranean area this diluvial Loess is probably 

 represented in part by a very widely spread red soil 

 or earth. 



Having now sketched the geographical distribution 

 of the Bubble-drift, in its various forms, I would 

 direct attention to a few of the more typical exhibi- 

 tions of it in several areas affected by this temporary 

 submergence of the land, and their interpretation. 



