393 



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, excavation, and the operation of the stream. The length of 

 the channel made for conducting the water was 20 yards and its 

 width 3 feet j and at the end of the channel a pit was made nearly 

 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 ^th of a circle of 1 8 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 

 the foot of which Argostoli is built, nowhere exceeds 400 feet in 

 height, sloping gradually towards the sea, and is surrounded by com- 

 paratively shallow water. The whole of the ridge consists apparently 



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