Vol. 69.] AGE OF THE SUFFOLK VALLEYS. 583 



as ' glacieluvial gravels.' 1 These are usually high-level gravels 

 occurring up to 250 feet 0.1)., but are sometimes found extending 

 down into the valleys. There are two types, one of which is some- 

 times seen to overlie the other (as at Woolpit). One is an intensely 

 chalky gravel, often associated with chalky sand and oceasionally 

 bedded at a high angle, containing chiefly pebbles of Chalk and 

 Jurassic fossils, with some flint. The other type, which forms 

 larger masses, is a highly-ferruginous flinty gravel, devoid of any 

 signs of bedding, with a loamy matrix. The bed frequently con- 

 tains twisted wisps of loam and Chalky Boulder Clay. The flints 

 are often large, with the same irregular shape as that which they 

 possess in the Chalk, but bearing evidence in their crust (especially 

 upon knob-like projections) of very great battering. Many are 

 broken or angular, and nearly all are fresh, black or dark-brown, 

 translucent, unaltered flint. There has been no sorting into sizes — 

 large and small flints and, less commonly, other rocks forming a 

 higgledy-piggledy mixture. The flints occur in all positions, many 

 being set up on end. Usually 12 to 14 feet of this deposit is the 

 maximum thickness, and exposures are met with at Drinkstone, 

 Tostock, Woolpit, and Elmswell, near Bury St. Edmund's, Newton 

 and Great Waldingfield near Sudbury, Creeting, Barking, Rush- 

 mere, and Ipswich in the Gipping Valley, and other places. They 

 were probably the final result of the glaciation of the district, 

 left sporadically by torrential streams on the recession of the ice. 

 Their formation is thus somewhat similar to that of the ' Cannon- 

 Shot' Gravels of Norfolk, described by Mr. F. W. Harmer ; and, 

 but for the fact that their constituent boulders are not beautifully 

 rounded like those in some of the occurrences of the ' Cannon- 

 Shot ' Gravels, they find their closest parallel therein. 



In addition to the Drift deposits described above, sands and 

 gravels, and, more rarely, loams occur, forming river-terraces. 



The object of the following notes is to show that the Suffolk 

 valley-system — at any rate, in its main features — is more recent 

 than the late Pliocene deposits, but older than the Upper Boulder 

 Clay of the area under consideration. In no way can the chief 

 valleys be regarded as of post-Glacial age. 



One of the few references to the valley-system of Suffolk, and 



1 [For want of a better term, I have previously referred to these gravels as 

 ' morainic/ Prof. J. W. Gregory, after a visit to East Auglia with Mr. G. 

 Slater and myself, has drawn my attention to the term ' glacieluvial ' proposed 

 by him ('The Polmont Kame' Geogr. Journ. vol. xl, 1912, p. 169 ; 'The 

 Polmont Kame, & on the Classification of Scottish Kames ' Trans. Geol. Soc. 

 Glasgow, vol. xiv, pt. 3, 1912, p. 199) for such glacial deposits which are 

 colluvial, to use Merrill's classification, rather than alluvial. There is need 

 for such a term in East Anglian glaciology, as the gravel-deposits under con- 

 sideration are not fluvio-glacial, for they occur in broad spreads formed by an 

 irregular wash of water down a slope, and not by streams ; they are not 

 morainic, for their material appears to have been deposited bv water. — 

 P. G. H. B., Dec. 13th, 1913.] 



2q2 



