14 
SHEPPARD : INTER-GLACIAL GRAVELS OF HOLDERNESS. 
If, as pointed out in Mr. Kendall's letter, the ice-sheet oscillated 
over this area repeatedly, then it is quite conceivable that Cyrena 
fluminalis may have lived either in lagoons amongst the moraines, or 
perhaps even during the many deviations in the course of the 
Humber, produced by morainic obstructions, they may have lived in 
a portion of that river itself when it flowed across the site of the 
present Holderness. 
Mr. Reid has pointed out in the case of Kelsey Hill that it lies 
directly opposite the gap in the Wolds through which the Humber 
flows and probably flowed. 
Granted that these shells were either inhabitants of the area or 
that they were washed out to sea, their inclusion amongst the 
shoved-up contents of these Burstwick gravels is easily explained. 
It may be worth noting that the species has been found in the truly 
marine Red Crag, but there is associated with beautifully preserved 
marine shells with paired valves, which obviously lived on the spot. 
In conclusion, I may be allowed to sincerely thank Mr. Kendall 
for permission to make use of his letter, as well as for valuable 
assistance in other directions ; and also Mr. Platnauer, who was put 
to no small amount of trouble in identifying the mammalian remains. 
