176 REV. THOMAS BROWN ON THE OLD RIVER TERRACES. 



our rivers, nothing could be easier than to explain the whole phenomena of 

 these terraces with their high-level gravels. 



There need be little difficulty as to where the materials would be found 

 which were to form the great masses of these sandy and gravelly deposits. The 

 escars and the associated mounds sufficiently show what immense accumu- 

 lations of such materials had been provided under the action of ice, and perhaps 

 of the under-ice rivers of the glacial period. If exposed to the action of torrents 

 on a somewhat greater scale than those of the Moray floods, such materials 

 would soon be disposed of. No great lapse of time need to be supposed. If 

 the whole of the above results in Morayshire were produced in about twenty- 

 four hours, it would be difficult to say what might not be done by a single 

 century of such inundations. 



Note. — In this paper attention has been called to the absence of marine fossils from the terraces 

 at Bridge of Earn and elsewhere. If such fossils should occur, it would be important to inquire 

 whether they belonged to the time when the terraces were formed. Sometimes portions of antecedent 

 deposits are overlaid or enclosed by the materials of the terraces — portions of rock in situ, for example, 

 or of boidder clay. In the same way there might be found portions of those marine shell clays which 

 belong to a previous period. 



