THE MEDITERRANEAN NATURALIST 
7 
which runs between Malta and Cerigo — a deep 
valley running in a direction from ncrth to south, 
and with a depth varying from 3500 to 4000 
metres, the descent being much more abrupt on 
the Greek side than on the Italian and Sicilian 
side. Experiments as to light showed that the 
waters are more transparent near the African 
coast than in the northern portions. There, white 
metal plates were discernable at a depth of nearly 
144 feet. Sensitive plates were still found capable 
of being acted upon by a light at a depth of nearly 
550 yards (2 | furlongs), at a point 200 marine 
miles north of Ben-Ghazi ; on being drawn up 
they were found to have been blackened. 
The acid constituents of the sea- water seem to 
be the same at the greatest depth as near the 
surface, nor is any difference in the quantity of the 
ammoniaeal constituents perceptible between the 
upper and the lowest levels, with the exception 
that every where close to. the bottom the quantity 
of ammoniaeal ingredients is notable. 
The deep sea region of the Eastern Mediterranean 
is very poor in animal life. A dredge at a depth 
of 3000 metres brought up no animal specimens 
at all, but at a depth of 2000 metres leaf-formed 
algce were discovered similar to those found at 
the same depth in the Atlantic by the Panton ex- 
pedition. Bci. Gos. 
Formation of Coral reefs in recent seas. 
The question of the origin and nature of coral 
reefs was fully discussed by I)r. John Murray at a 
recent meeting of the Royal Society of Edinburgh. 
He first referred to the experiments that have 
recently been made with reference to the secretion 
and solution of carbonate of lime. He said that 
carbonate of lime remains are found in great 
abundance at the sea bottom in shallow waters, but 
the amount steadily diminishes as the depth in- 
creases, until at 4,000 fathoms almost every trace 
has disappeared. 
This is due to the solvent action of the water 
as the organisms slowly fall to the bottom. 
Everywhere within 500 fathoms of the surface the 
ocean teems with life. The Greely expedition 
was starving within ten feet of abundant food, 
which might have been obtained by breaking a 
hole through the ice and using a shirt as a drag-net. 
Dr. Murray then proceeded to discuss his theory 
of the formation of coral reefs, bringing forward, 
in reply to objections by Dana and others, some 
recently obtained facts regarding the existence of 
shallow regions in what is, on the whole, deep 
water. He showed that carbonate of lime is con- 
tinually produced in great quantity in warn’ 1 * 
tropical water by the action of sulphate of iimA 
in solution on effete products. 
This explains the great growth of coral on 
certain shores in tropical regions. 
The absence of coral on certain shores in 
tropical districts is explained by the uprise of 
cold water due to winds blowing offshore. 
The paper was illustrated by an elaborate 
series of lime-light diagrams. 
Notes on the discovery 
of a “Pleistocene Bed” at Gozo. 
In the year 1874 a letter signed by Messrs 
Fielden and Maxwell appeared in the Maltese 
Journal U H Barth,'’ in which attention was drawn 
to a post-pliocene deposit, that was said to have 
been discovered in the vicinity of Gala Duera and 
II Kala in Gozo. A specimen of the deposit 
together with a number of shells that were found 
in the bed, were forwarded to Prof: Seguenza, 
who, after having examined them, expressed an 
opinion that the discovery was one of much 
importance. (1) 
From that time to this, no further attention 
appears to have been paid to the matter. During 
the latter portion of the summer of 1890, while 
engaged in investigating the geology of the Dueira 
district, I first discovered evidences of the bed 
to which Messrs Maxwell and Fielden had 
alluded seventeen years before. 
Gala Dueira is a small bay, which is situated at 
the western extremity of Gozo. 
Its southern and eastern shores are bounded by 
mural cliffs of Lower Coralline Limestone, that 
tower above the level of the sea to a height, 
which varies from 150 to 200 feet. (2) 
In consequence of a fault, that extends from 
Monsciar at the head of Uied-el-Arab to Dueira, 
the eastern boundary of the bay has been let clown, 
(1 ) It Barth. 1874. 
(2) The following table s hows the order in which 
the Maltese formations occur. 
Dr. Murray’s classification. 
Capt. Spratt & Dr. Adam’s 
classification. 
I. Upper Coral. Limestone 
II. Greensands 
III. Clay beds 
IV. Globigerina Limestone 
V. Lower Coral. Limestone. 
I. Upper Coral. Limestone 
II. Sand bed 
III. Marl beds 
IV. Freestone 
V. Lower Limcstoi\e s - 
