188 
Correspondence — Dr. Ottokar Feistmantel. 
during the deposit of our Eocene series differed widely at each period. 
■^ ow my acquaintance with the Eocene formation, and with its 
Eauna in various ways, 1 is somewhat more than Mr. Gardner gives me 
credit for; and I distinctly traverse his Suggestion that the Eauna 
of the beds he natnes affords (when allowance is made for varying 
conditions of bottom and depth, and for the difficulty in making 
comparisons between faunas of wbich some are marine, some fluvio- 
marine, and some fluviatile, as is the case with these beds) any indica- 
tion whatever of a diversity of climate. Fortifying the opinion which 
I have forrned from my own acquaintance with these beds, and with 
their E auna, by that to the same purport of my father, who has made 
the study of the Tertiary Mollusca the occupation of the greater part 
of a long life, I contend that, so far as the past can be judged from 
what is known of the present, this fauna is of tropical character 
throughout. It was once thought that the mollusca of the Thanet 
sands indicated a colder climate than did those of the beds which 
succeed it, but the subsequent diseovery of a Hautilus in these sands has 
made even that view difficult to be maintained. Moreover, not only do 
the Eocene beds of Western Europe present this character, but the 
close similarity between Eocene mollusca found in the Aral-sea region 
and those from the English and French beds indicates that this climate 
prevailed under nearly the same latitude as far, at least, as the 
meridian of 60° East longitude. 
I have trespassed thus much on your space, to vindicate the Opposi- 
tion which I offered to Mr. Gardner’s hypothesis of oscillations of 
climate during the Eocene period; and i could pursue the subject 
further, as well as offer reasons for disagreeing from his alternative 
theory of the existenee of a mean annual temperature, which permitted 
the growth of sub-tropical and more temperate forms side by side ; but 
as he expresses his intention of not entering into any discussion with 
me, this would be undesirable, as I should be sorry to tempt him into 
any descent from the serene elevation on which he has placed himself. 
I would, however, observe that, although the explanation which I 
offered as to the Hampshire Flora seemed to me the mostobvious in that 
particular case, and although I do look upon both of Mr. Gardner’s 
hypotheses as remote from the truth, I have nothing to say in Opposition 
to Prof. Heer’s view that difference of climate according to latitude did 
not, so far as it is evidenced by fossil Vegetation, begin to show itself 
until late in the Mesozoic division of the Earth’s history. 
Seakles V. Woon, Jun. 
THE GONDWANA SERIES OF INDIA. 2 
Sin, — I have some remarks and corrigenda to add to my article on 
the Gondwana Series of India. 3 
First, as regards the Classification of the whole area, as used in the 
above-mentioned paper, I have to state that it should be, properly, as 
follows : 
1 Amongst them, the original and first disinterment from the Hampshire cliff, in 
association with my father (now thirty-four years ago), of the remains of “Alligator, 
Turtle, and other lteptiles,” to which Mr. Gardner in his paper refers. 
2 The publication of this letter has been by an unfortunate oversight delayed a 
month. — E dit. Geoe. Mag. 
3 See Geol. Mag. Dec. II. Vol. III. p. 481. 
