408 WARREN UPHAM, KSQ., M.A., F.G.S.A., ON 
of the Ice age. The many other sections in this valley 
display ice-floated sandstone blocks and deformations of the 
strata attributable to the melting of masses of river ice; 
but these disturbed conditions were absent when human 
implements and the bones of the mammoth, the woolly 
rhinoceros, wild horse, urus, stag, reindeer, lion, and hyena 
were mingled in the Menchecourt gravel and sand beds, 
which are about 20 to 30 feet above the sea level, under 
subsequent deposits of 20 feet of loam and clay, the surface 
being about 50 feet above the sea or 40 feet above the river. 
The sections of Menchecourt, Mautort, etc., are further 
distinguished from others at higher levels near Abbeville, 
and from all at both low and high levels along the upper 
part of the valley, by their containing marine shells. Lyell 
writes of their mode of occurrence at Menchecourt as 
follows :— 
In the lowest beds of gravel sand and in contact with the chalk, flint 
hatchets, some perfect, others, much rolled, have been found ; and in 
a sandy bed in this position some workmen, whom I employed to sink 
a pit, found four flint knives. Above this sand occur beds of white 
and siliceous sand, containing shells of the genera Planorbis, Limnea, 
Paludina, Valvata, Cyclas, Cyrena, Helix, and others, all now natives of 
the same part of France, [except Cyrena [Corbicula] fluminalis, which 
no longer lives in Europe, but inhabits the Nile and many parts of Asia, 
including Cashmere, where it abounds. No species of Cyrena is now 
met with in a living state in Europe. Mr. Prestwich first observed 
it fossil at Menchecourt, and it has since been found in two or three 
contiguous sand-pits, always in the fluvio-marine bed. 
The following marine shells occur mixed with the fresh-water species 
above enumerated: Buccinum undatum, Littorina littorea, Nassa reti- 
culata, Purpura lapillus, Tellina solidula, Cardium edule, and fragments 
of some others. Several of these I have myself collected entire, though 
in a state of great decomposition. . , . They are all littoral species 
now proper to the contiguous coast of France. Their occurrence in 
a fossil state associated with fresh-water shells at. Menchecourt had 
been noticed as long ago as 1836 by MM. Ravin and Baillon, before 
M. Boucher de Perthes commenced the researches which have since 
made the locality so celebrated. The numbers ,since collected preclude 
all idea of their having been brought inland as eatable shells by the 
fabricators of the flint hatchets found at the bottom of the fluvio-marine 
sands. 
This part of western Europe was then slightly lower than 
now, indicating, with the absence of ice before noted, that 
the time represented by these sections preceded the great 
uplift of this region, which culminated in the maximum 
European glaciation. But earlier, and probably continuing 
with increased vertical and geographic extent during the ear ly 
