NOTES ON ESSEX GEOLOGY. 267 
of Westleton, etc. In the case of Clacton the gravel may be 
still newer. 
Our nearer neighbours, the gravels of High Beach and 
Jacks Hill, I have practically classed, as Prestwich does, with 
the Westleton Beds, although not using that name, but being 
content with “ pebble-gravel,” on the Geological Survey Map 
1 N.W. 
The conclusions drawn as to the relation of the Westleton 
Beds to the Glacial Drift of the Thames Valley depend so largely 
on the correctness of the classification, as given above, that I 
think we should be cautious in accepting them until we can be 
more certain, and certainty in the classification of gravels seems 
often to be far off. 
Part iii. of this set of papers treats of the Hill Gravels of the 
Warley and Brentwood Groups, including those of Rayleigh 
and Langdon Hill. Whilst saying that “ there can be no doubt 
of the Pre-Glacial age,” the author hesitates to include them 
with his Southern Drift (to which this part chiefly refers), though 
he does not class them as Westleton Beds. 2 I cannot but think 
that not only have some of these gravels “ the essential character 
of a Bagshot pebble-bed,” but that they are such, and not 
Pre-Glacial Drift. 
The relation of these various beds to the erosion of the 
Weald is really beyond our Essex view ; but in the genesis of 
the Thames we are concerned (though topographically more 
with its latter end). The author (who thinks that this origin 
dates “from late Pre-Glacial or early Pleistocene times”), 
well says : “ This is a branch of geology which opens some very 
large and interesting problems. . . . Owing to the vast erosion of 
the surface, the evidence respecting the older Drifts is generally 
very fragment ary, and has often been entirely swept away. 
Some speculation is therefore unavoidable, though it is essential 
that the consequences that may result from hypothetical assump¬ 
tions should be in harmony with the results ot observation.” 
( pp . 179, 177). 
In this year I gave some details of the deep channel of 
Drift in the head-part of the valley of the Cam, which channel 
had been proved to a depth of 340 feet, without reaching the 
bottom, carrying the Drift to considerably below sea-level. 4 
2 Quart. Journ. Geol. Soc., Vol. xlvi., pp. 162-165,177. 
3 Quart. Journ. Geol. Soc , Vol. xlvi., pp. 333-340. 
