74 Geological Society. 
at Grays Thurrock and Brentford. At the former place the author 
recognizes the true pliocene assemblage of Lozxedon priscus, Euele- 
phas antiquus, Hippopotamus major, and Rhinoceros leptorhinus ; but 
the group of mammals found at Brentford, according to the published 
determinations, indicate the close proximity of both the pliocene 
and post-pliocene faune at different levels of the same section. The 
Grays Thurrock deposits, and the lower beds at Brentford were 
inferred to be of an earlier age than any part of the Boulder-Clay 
or Sill. 
The grouping of the E. primigenius, Rhinoceros tichorhinus, Bu- 
balus moschatus, &c., in the newer gravels of England and elsewhere 
was next dwelt upon, as affording an additional clue to the tracing 
of the several characteristic mammalian faunas over the European 
area, 
To the possible objection of there being too many large Probos- 
cideans grouped in one fauna, the author replied that the bones of 
animals of three distinct species actually occur together in one 
stratum in Italy, and that six species are found in deposits of one 
age in the Sivalik hills. 
Dr. Falconer concludes that the same mammalian fauna existed 
throughout the period during which both the Crag and the fluviatile 
beds of the Thames Valley were being deposited ; and that a chro- 
nological division of the newer Tertiaries into older Pliocene, newer 
Pliocene or Pleistocene, and Post-pliocene is untenable; too much 
stress having been laid by authors upon the shell-evidence on this 
point. At the same time, it is not meant to be implied that all the 
species of the fauna ranged everywhere throughout the area; some 
in all probability were peculiar to the south, and others to the 
north. 
The presence of the Hippopotamus in the pliocene deposits was 
pointed out as being of great importance in indicating the character 
of the pliocene land, which, extending between England and the 
Continent, must have afforded a great system of rivers and lakes, 
and probably had a comparatively warm temperature, as late as the 
deposition of the Grays beds, where also (as is well known) occur 
some southern freshwater shells, now extinct in England, 
After some remarks on the negative evidence afforded by this 
mammalian fauna with regard to the supposed refrigeration of 
the land during the Pliocene period, Dr. Falconer reviewed the 
opinions of some English geologists on the physical conditions and 
faune of this region during the newer Tertiary epoch, especially 
the views of Mr. S. Wood, Mr. Prestwich, and Mr. Trimmer; and 
concluded with a few remarks on the occurrence of E, antiguus in 
the Cefn and Kirkdale Caves, and of H. primigenius in Kent’s Hole, 
and on the non-existence of EH. primigenius south of the Alps, and 
its restriction in the United States of America to the Northern and 
Central States. In the Southern States and in Mexico a distinct 
fossil species, Euelephas Columbi, hitherto undescribed, occurs along 
with remains of Mastodon, Mylodon, Megatherium, Horse, &c, 
