220 STATU ER : NOTES ON THE DRIFTS OF THE HUMBER GAP. 
The Chalky Gravel (2) of the South Ferriby Section appears to 
be of the same character as that of the dry Wold Valleys, and to 
have had the same origin.'*' 
Conclusions. — The following are the chief deductions to be 
drawn from the facts as above recorded : — 
1. The materials which compose the North and South Ferriby 
glacial sections show conclusively that the agency which produced 
them did not flow from the higher legions of the Humber valley, as 
the general shape of the ground and high land to the west would 
suggest, but came, on the contrary, from the eastward, the material 
of the deposits agreeing exactly with that of the Holderness sections. 
2. The Ferriby Sections reveal an Upper and a Lower Boulder 
Clay of entirely different types, separated by a line of erosion, prob- 
ably corresponding to certain wide-reaching divisions of the Yorkshire 
coast. 
3. The detailed study of the sections confirms the view originally 
put forward by Mr. S. V. Wood, that the glacial beds on the opposite 
sides of the Humber were once continuous, and have since been cut 
through by the river. 
4. 'We ridge of glacial material now bi-sected by the Humber 
at North and South Ferriby, has at one time constituted a much 
more prominent feature than at present, when it is nearly buried 
beneatli the later warps. Its original outline suggests a moraine-like 
bar across the Humber Gap. 
5. If the Geological Survey are right in referring the gravel 
capping the Red Cliff Section to late glacial times, the High-level 
Warp Series overlying the boulder clay cannot be of later date. It 
would thus agree in stratigraphical position with the Hilderthorp 
Warps near Bridlington. 
6. The position and relations of the glacial beds in this section 
indicate the former presence of a mass of land-ice in the bed of the 
North Sea, possessing a tendency to press westward upon the land, 
the ice west of the Wolds being insufficient to keep back the 
intruder. 
For the diagram illustrating these notes I am indebted to Mr. 
W. H. Crofts, and for valuable help in many other ways. 
* Survey Memoir. — The Geology of the Country between York and Hull, p. 34. 
