246 CROFTS : notes on Alexandra dock extension, hull. 
tliese works are glacial and post-glacial. The strata generally, 
after tlie removal of the debris from the Alexandra Dock, 
being as follows : Humber warp, shell bed, marl, peat, red 
stoneless glacial clay, gravel and boulder clay. 
The eastern wall trench was most favourable for detailed 
observation. At the southern end the strata were as follows : — 
ft. in. 
Laminated warp ... ... ... 12 0 
Shell bed 0 3 
Silt 1 6 
Shell bed 10 
Glacial gravels ... ... ... 11 0 
Compact boulder clay ... ... ... 3 0 
Towards the north the surface of the boulder clay rises, 
a bed of stoneless red clay intrudes into the upper portion of the 
gravels, a peat bed makes its appearance, one of the shell beds 
disappears, and the toe of a sand bank is introduced under the 
warp. At the north end of this trench we find there are two 
distinct beds of boulder clay separated by gravels, the red 
stoneless clay having died out, otherwise the section does not 
vary from that last described about half way towards the southern 
end of the trench. 
The floor of the dock itself is formed in the glacial gravel 
over a large part of its area, but towards the northern end the 
upper boulder clay rises above this level. This gravel no doubt 
largely contributed to the ease with which these works were 
completed, the flood water availing itself to a large extent of 
the course of its glacial predecessors. 
The boulder clay forming the bottom of the .series is a very 
compact stifl" grey clay, with a large number of striated Chalk 
boulders in addition to the prevalent basalt, Cheviot porphyrites, 
Mountain Limestone, and the usual rocks of the boulder clays of 
Holderness, except that no specimens of Scandinavian origin were 
noted. This fact is the moi-e remarkable as in the coast sections 
of Holderness the lower the bed the more numerous the Scan- 
dinavian rocks become. This clay may be either of the clays 
