336 Superficial Gravels and Clays, [July, 
described by Col. Lane Fox as occurring at the base of the 
gravels in Brown’s Orchard, may be the same, but he does 
not mention any fresh-water shells. As at that locality it 
also contained some rounded and angular pebbles, it was 
probably a slightly drifted bed mixed with the lower part of 
the sandy gravel. At Flora Villas the perfect shells of the 
species of Unio and Pisidium , with the two valves united, 
and the absence of all foreign materials, leads me to think 
that it was in place, and quite undisturbed since its original 
deposition. 
I believe there are two distinct faunas represented in the 
lower beds, though the remains are often now found mixed 
together. The oldest of these two faunas is characterised 
by containing the remains of Elephas antiquus , Rhinoceros 
hemitcechus , Hippopotamus major, and Cervus dama var. 
Clactoniensis. It also contains the following species that 
occur in the succeeding formation : — Equus caballus, Bos 
primigenius, Elephas primigenius, Cervus elephas, Ursus ferox 
prisons, and Felis leo. This is the fauna that Col. Lane Fox 
found in the low-lying ground between ACton and Brentford. 
A single piece of the antler of a reindeer was found at the 
same place, but I think its presence may be explained by a 
slight mixture of the two faunas, as there are other signs of 
the partial reconstruction of the deposit. 
The characteristic mammals of the second fauna are the 
woolly rhinoceros and the reindeer. Both faunas were ori- 
ginally contained in loose incoherent sands or in peat beds, 
and at the time of the violent outspread of the subangular 
gravels were more or less mixed together, and even 
caught up and distributed through the gravel. As they lived 
at the same time, one occupying a northern and the other a 
southern zone of country, they may sometimes have over- 
lapped each other’s range in their summer and winter mi- 
grations, as has been urged by Sir Charles Lyell and Prof. 
Boyd Dawkins. 
The mammoth appears to have had a very wide range, and 
occurs in all the deposits from the Cromer forest-bed up to 
the diluvium, and is found associated, on the one hand, with 
such a southern form as Rhinoceros etruscus, and, on the 
other, with such northern forms as the reindeer and woolly 
rhinoceros. 
The molluscan remains found in the Brentford beds favour 
the supposition of two faunas. In the lower beds occur 
Unio littoralis and Hydrobia marginata, both of which are 
southern mollusks not now found in England, and which 
lower down the Thames are found associated with the still 
