Geological Society. 573 
new red sandstone by which the marls are surrounded, though, from 
the covered nature of the ground, the connexion of the two forma- 
tions cannot be ascertained. In mineral aspect the lowest beds at 
Collyhurst are said to agree with the upper red marl of Lincolnshire 
and Cheshire, and to be distinguished from it only by the presence 
of fossils and the absence of salt ; while the Collyhurst strata differ 
from the lower red marl, in colour, fracture, and the organic remains. 
In accounting for the presence of these fossiliferous marls in the 
situation described, and their absence from the top of the new red 
sandstone in the immediate neighbourhood, the authors suppose that 
the marls were deposited in a hollow of the new red sandstone, and to 
have been, therefore, protected from denudation. 
A notice, by Francis Offley Martin, Esq., inclosing communications 
from Col. Brown and Lieut. Laurence, of the Rifle Brigade, and Mr. 
Stevens, on the streams of sea water which flow into the land in the 
island of Cephalonia, was next read. 
These communications were procured by Mr. Martin at. the request 
of Mr. Lyell. 
Lieut. Laurence’s letter is dated 31st of May, 1835, and contains 
an extract from an account sent to him by Mr. Stevens of the na- 
ture, excayation, and the operation of the stream. The length of 
the channel made for conducting the water was 20 yards and its 
width 3 feet ; and at the end of the channel a pit was made nearl 
100 square yards in extent, and to the depth of about 4 feet below 
the level of the sea. On opening the sluice a stream of 150 square 
inches rushes into the pit with a velocity of 20 feet a second, and 
down a channel in the form of a segment of 4th of a circle of 18 feet 
diameter. A constant discharge of this stream raises the water in 
the pit to within 2 feet of the top of the arched channel. The stream 
escapes through the fissures in the pit, but the direction which it 
afterwards takes has not been well ascertained, though shafts have 
been sunk for that purpose. In these shafts water of the same de- 
scription with that in the pit is found, rising and falling in the same 
manner. Mr. Laurence also states that when the sluice-gate is shut 
down after a very considerable discharge of sea water into the pit, 
the water in the pit falls a few inches lower than it was previously to 
the discharge ; but is afterwards raised to the usual level by the 
freshwater springs. 
Mr. Stevens’s letter, dated the 28th August, 1835, gave an account 
of the making of the excavation, and states that the experience of a 
year and a half had proved that the stream is not liable to any perio- 
dical change. 
Col. Brown’s communication bears date the 27th of August, 1835, 
and gives an account of the physical features of the island, the nature 
of the excavation, and the probable manner by which the subterra- 
nean current is disposed of. 
On the eastern side of the harbour of Argostoli the country rises 
abruptly from the shore to a considerable elevation, and then more 
gradually until it is lost in one of the great ridges which intersect 
the island; but on the western side the narrow peninsular ridge at 
