Fune 10, 1886] 
the Eocene period, some others from the Oligocene ; 
while the most recent Miocene and Pliocene deposits 
contain a fauna in process of decay : the deep-sea fauna 
of the banks of the Aral is substituted by a shallow-water 
fauna, and the Nummulite banks disappear. The chief 
fossils are teeth of sharks, some Lamellibranchiata, and 
a few oysters (Sphenia rostrata, Lamk. ; Wodiola sub 
carinata, Lamk.; MM. jeremejew?, Roman.; Alligator 
darwini, Ludw.; Ostrea raincurt?, Desh.; O. longirostris, 
Lamk., &c.). These features, as also the extension of 
pudding-stones, especially on the outskirts of the Tian- 
Shan, are indicative of their littoral origin. The same 
distinction appears as to the minerals they contain. 
Several great beds of gypsum, brown-coal, and _bitu- 
minous slates are found in the Tertiary deposits around 
Lake Aral, as also naphtha in the Balkhan mountains ; 
but both naphtha and brown-coal are absent in the Tian- 
Shan deposits, which contain, on the contrary, salt, 
together with gypsum. 
The Post-Pliocene Aral-Caspian deposits can hardly be 
delimitated from the Tertiary deposits. Their maximum 
thickness does not exceed roo feet. Both in the Black- 
Sands (Kara kum) and the Red-Sands (Kyzyl-kum) they 
consist of a sandy clay which often passes upwards into a 
clayey sandstone. As to their petrographical features, 
they are the same from the Volga to the foot of the Tian- 
Shan. The fossils they contain (Cardium edule, Dreys- 
sena polymorpha, Neritina liturata, Adacna vitrea, and 
Hydrobia stagnalis in the Kara-kum ; Léthoglyphus 
caspius, Fydrobia stagnal’s, Anadonta ponderosa, and 
the Spongia described as Metschnihowia tuberculata by 
M. Grimm in the Kyzyl-kum) are all now living in the 
Caspian and Lake Aral, and precisely in the littoral 
shallow-water zone. 
What are the limits of this immense Post-Pliocene 
basin surely forms one of the most interesting problems 
of geology, and they can already be determined approxi- 
mately. In the west, the Ergeni hills (which run due 
south of the great Tsaritoyn bend of the Volga) form its 
western shore '—a great gulf extending along the broad 
valley of the two Manych rivers towards the Black Sea. 
Further south it must have been much nearer to the 
present shore of the Caspian, with a broad gulf to the 
west in what is now the valley of the Kura. How far this 
gulf extended towards the north remains still unsettled. 
The evidence derived from the Dreyssena polymorpha, 
found as far north as the Samara winding of the Volga, 
is still contested by MM. Méllerand Grimm—this species 
of Dreyssena being a too cosmopolitan one; but the 
discovery of a few Caspian mussels even further north, 
towards Simbirsk, as well as the orography of this region, 
make one incline to the opinion that a narrow gulf of the 
Aral-Caspian Post-Pliocene sea extended almost as far as 
the mouth of the Kama, with a wide lake filling up the 
Oka depression of the Volga and communicating with 
the sea by an outlet. It is known that this basin extended 
towards Lake Aral and further east, with a penin- 
sula which entered it from the north, and which is now 
known as the Ust-urt and Mugo-djar hills. How far it 
_) Prof. Barbot-de-Marny, whose deep insight and keen observation are so 
highly esteemed, extended these limits further west. Several considerations 
derived from the orography and physical geography of the region give. in 
my opinion, great probability to M. Moushketoff’s view on the question. 
He has also had the opportunity of making a tk i 
feo y ig a more thorough exploration of 
NATURE 
119 
extended towards the east remains still unsettled. M. 
Moushketoff only mentions the supposition of the late 
M. Severtsoff as to the connection which existed between 
Lake Aral and Lake Balkhash. However probable this 
connection, we ought to take into consideration the latest 
researches of Russian zoologists, according to which the 
fauna of Lake Balkhash would have much more kinship 
with the lakes of Central Asia than with the fauna of 
Lake Aral. If this fact is confirmed, we should probably 
distinguish two different periods—an earlier and a later 
one —during which last the connection between Lake 
Balkhash and Lake Aral was broken, but continued be- 
tween the former and the eastern lakes of Central Asia. 
As to the southern limits of the Aral-Caspian basin, 
they cannot yet be determined with certainty. Aral- 
Caspian deposits are wanting in the middle parts of the 
Kyzyl-kum plateau, so that the southern shores of this 
basin must have been somewhere in the latitude of the 
Bukan-tau mountains. Further east they ran in a more 
southern latitude. In the Sary-kamysh depression and 
for 160 miles further south we again find Aral-Caspian 
mussels, as far as the Bala-Ishem wells, and in this region 
the Uzboy (formerly considered as the old bed of the 
Amu) disappears. South of Lake Aral they hardly reach 
the latitude of Mery. From all these data, M. Moush- 
ketoff concludes that the basin consisted of two different 
parts—the Caspian and the Aral part—connected by a 
narrow outlet passing by the base of the Balkhan mountains. 
The eastern portion was shallower than the western ; it 
had more islands, and its organic life was poorer. It was 
also subdivided, in its turn, into two parts connected by 
the Aibughir outlet. 
As to the drying up of this basin and its subsequent 
modifications, which M. Moushke’'off attributes in great 
part to the agency of the wind, we shall devote to them a 
second article, inasmuch as the author’s observations on 
the dunes and moving sands deserve special attention. 
Bak. 
(To be continued.) 
THE NATURALIST’S DIARY 
The Naturalist’s Diary. Arranged and Edited by Charles 
Roberts, F.R.C.S., L.R.C.P., &c. (Swan Sonnenschein, 
Le Bas, and Lowry, Paternoster Square). 
apts book may be described as a most excellent vade 
mecum and guide to any person who not only 
wishes to keep a phenological diary, but who wishes to 
know what to enter therein. The preface and introduc- 
tion show forth the principles which have guided the 
author in making this compilation, and the important 
services it may be made to render to biologists and to men 
of science, as well as to practical gardeners, agriculturists, 
sportsmen, and residents in the country generally. It is 
also recommended to the notice of tourists, and especially 
to those who find themselves perchance perforce anchored 
in some one of our numerous health resorts, cut off from 
their usual avocations. Mr. Roberts’s observations have 
been made on the breezy downs of Marlborough in con- 
nection with the Marlborough College Natural History 
Society, 1864-84. They include registration of mean, 
maximum, and minimum temperature in sun and shade, 
“accumulated temperature” above 42° day-degrees, baro- 
| metrical observations, rainfall, and direction of wind. 
