159 
there both Eocene and L. Oligocene series or „Transition Eocene- 
Oligocene Beds“. This work by Mihailovski is at the same time the 
last palaeontological study of the fauna of these beds that I know of, 
but in the meantime several papers on the stratigraphy of these beds 
were published during the period between V. Koenen’s and Mihai- 
lovski’s publications. 
Also several other authors, in their papers dealing with the 
Geology or Physical Geography of this or adjecent regions, made 
some contributions to the stratigraphy of these beds. It will be of 
interest to mention some of them. Romanovski') considers them 
as Eocene. L. Berg?) in his monograph „The Aral Sea“ follows V. 
Koenen’s opinion. V. Bogachev,*) who in 1907 made his resear- 
ches in a great many localities all along the northern shore, came to 
the conclusion that the beds in question are of the L, Oligocene 
age, but by their lowest part they might be equivalent to Sokolov’s 
„Kiev Series“, i. e., uppermost Eocene. He recognises two horizons, 
viz.: the lower of plastic clays and sands and the upper of gypsi-- 
foreus clays and sands with the intercalation of gray sandstone.*) 
He also points out that there exist certain differences between the 
faunas of these two horizons, but concludes that these must be only 
facial differences. 
The account of the fauna from the Tertiary Beds of the Aral 
Sea given in the following pages, is based on the collection of Mr. 
W. Batesen. In 1886 he visited the whole northern shore between the 
Perovski Gulf, the mouth of the Syr-Daria, and lake Chalkar, for 
the purpose of making scientific investigations. On this journey 
he collected a large number of well preserved fossils from several 
localities of this area, viz.: Togus-Ken, Turanghul, Termenbes, 
Perovski Gulf, Kum-Bar-Sai. Togus-Ken is about ten miles 
north of the shore of the Paskevich Gulf, and about 29 miles W. 
of Turanghul.*) Kum-Bar-Sai is a valley on the north-west shore 
of Lake Chalkar. Tol-Sai is about 50 miles N. E. of the town of 
Irghiz, in the direction of Chalkar. The greater part of the collection 
was presented by Mr. Bateson to the Sedgwick Museum, Cambridge, 
and the rest to the British Museum (Natural History Department). 
By the kind permission of the authorities of both museums 
I have had the privilage of studying Mollusca (Pelecypoda, 
1) G. Romanovski: Materialien zur Geologie von Turkestan. St. Peters- 
burg, (1880). 
) L. Berg: Reports of the Turkestan section of the Russian Imperial 
Geographical Society V (1908) (in Russian). 
3) Bogachev: Depöts tertiaires du litoral de ia mer d' Aral. Bull. Com. 
Geol. St. Petersburg XXVIII (1909) p. 63 (in Russian, resume in French). 
*) His table of the division of the beds is not very clear. One could no 
tell wheter he considers the whole part 9to be equivalent to the „Kiev Series“ 
or only part of it. He also puts Tongrian between „Harkov Series“ and „Pol- 
tava Series“. If the Harkov Series is equivalent to the Lattorfian (as Russian 
geologists assume) them Tongrian is used in neither of its meanings If Ton- 
grian is used as synonymous with Lattorfian then the „Harkov Series“ falls into 
Uppermost Eocene (which Russian geologists do not assume). 
’) Judging from information kindly supplied in a letter from Mr. Bateson. 
I am convinced that his ,Turanghul“ is identical with „I'ypaurası“* in Bogachev 
(l. c.). Perovski Gulf has also been visited by Bogachev. 
