403 
THE MEDITERRANEAN NATURALIST 
4,400 metres (2.406 fathoms), followed within a 
few miles further east by a depth of 4, 080 metres 
(2,230 fathoms), which are the greatest depths 
recorded in the Mediterranean. They have recei- 
ved from the Austrian Hydrographical Board 
the name of Pola Deep. The great depression of 
the Mediterranean must thus be shifted conside- 
rably east from its former central position on our 
maps. Another deep area was explored between 
(Jamba and Alexandria — the depths attaining 
from 3,310 metres (1,810 fathoms) some 20 miles 
south-east of Grandes Bay, and from 2,392 metres 
(1,208 fathoms ) to 2,120 metres (1,322 fathoms) 
within a short distance from Alexandria: the 
maximum depth sounded being 3,038 metres 
(1,678 fathoms) in 28° 39' 30" north latitude, and 
33° 19' 54" east longitude. The full result of the 
numerous and varied observations made on board 
the Pola will be published when all calculations 
have been completed : but several interesting facts 
are already indicated in the preliminary report. 
The highest temperatures were found in the first 
parts of the voyage, and are given as follows: 
From 80'8° F. to 69° in the first 50 metres (27 
fathoms); from 69° to 62*5° in depths from 50 to 
100 metres (27 to 55 fathoms); from 59° to 57° in 
depth of from 200 metres (110 to 547 fathoms) 
to 3,000 metres (1,640 fathoms). The lowest tem- 
perature (52k 0 ) was observed at the issue from 
the Adriatic Sea, at a depth of 760 metres (415 
fathoms); at 4,400 metres (2,406 fathoms) the tem- 
perature was 56°. It w T as observed last year that 
in the Central Mediterranean the density of the 
water and saturation with salt increased with 
depth, and the same was observed in the western 
part of this year’s cruise. But in the Eastern 
Mediterranean the density of the water varies but 
very little in the different strata (from 1 0297 to 
1*0300), and it is higher on the whole than in the 
West. The transparence of the water is very 
great in the Eastern Mediterranean ; in three cases 
a white disc was seen down to a depth of 54 me- 
tres (177 feet) but it disappaared from view at a 
depth of 32 metres (105 feet) at the above-mentio- 
ned station in the south-west of Cape Matapan. — 
Proceedings of the Royal Geographical Society, 
January , 1802. 
On the Occurrence of Concretionary 
Masses of Flint and Chert in the 
Maltese Limestones. 
By John H. Cooke, F. G. S., etc. 
The late AdmeralSpratt, R.N., (1) and Dr. John 
Murray, (2) of the “Challenger” Expedition, have, 
in their brochures on Maltese Geology, made allu- 
sion en passant to the occurrence of chert nodules 
in the Globigerina limestones of the Maltese islands 
Neither of these gentlemen, however, gave any 
details of the nature, mode of occurrence, or dis- 
tribution of the concretions, an omission which 
was probably due to the restricted area cf the ho- 
rizon at which the nodules are found, and to the 
irregular and sparse manner in which they are dis- 
tributed. 
The following notes on these points, which were 
collected in the course of my geological investiga- 
tions into the fauna, of the formation, may not, 
therefore, be without some .value to present and 
future students of Maltese geology. 
The Globigerina limestones in which the con- 
cretions occur occupy the second place in the 
ascending order of the Maltese formations. They 
attain a maximum thickness of about 250 feet, and 
comprise a series of layers or beds which vary in 
number in different localities from four to ten. 
Between the beds themselves the variations are 
but slight, and are of a chemical rather than of a 
lithological or a palaeontological character, consis- 
ting generally of a greater or lesser percentage of 
carbonate of lime occorcling to the extent to which 
the beds were influenced by the river-waters which 
brought down detrital products from the surround- 
ing continental areas. 
The following table shows the relative position 
and the more prominent characteristics of the 
sub-divisions. 
(1 ) “ This deposit often contains nodules of a 
dint}/ texture , viz., chert, in which are fish -scales.' 
The Geolog}/ of Malta and Gozo. Malta , 1854, p. '■ 
(2) u Nodules of dint and chert are found in some 
of the layers,'” The Maltese Islands , with special 
reference to their geological structure. Scut. Geog 
Mag.) September , ISOf g. 
