552 George Maw — Notes on the Mediterranean. 



stream, as it leads up to where the stream leaves the hill- side on the 

 edge of the plain, and evidently consists of matter it has deposited. 

 The stream, however, under existing conditions, could not have 

 maintained its course along the top of the ridge ; but if we suppose 

 the level marsh-land to have been at one time 20 or 25 feet lower, 

 and covered by the sea, the accumulation resting upon it is accounted 

 for, as the matter carried seaward by the stream at the point where 

 it now enters the marsh on the hill -side ; and on the rise of the land 

 and the appearance of the delta-like ridge above the sea, the stream 

 was naturally diverted to the lower level where it now flows. 



5th. The Coast Deposits of Post-Tertiary Age. — As my observa- 

 tions on these beds have been limited to the neighbourhood^ of 

 Gibraltar, I shall confine myself to noticing a few examples implying 

 an elevation of the coast-line at the eastern extremity of the Medi- 

 terranean. One of the most remarkable is the great mass of sand 

 flanking the eastern face of Gibraltar. As already noticed, most of 

 the escarpment is not now washed by the sea, being covered to a 

 height of nearly 700 feet by a huge deposit of sand in Catalan Bay. 



Eastern^Face of Gibraltar. S, Sand deposit of Catalan Bay. 



It has been referred to by several geologists ; and by some it has, I 

 think, been incorrectly described as blown sand : it has somewhat the 

 aspect of a sub-aerial talus, and from weathering and washing down, 

 the beds of loose sand on its sloping surface range with its inclined 



contour ; beneath this, however, it 

 is found to be regularly stratified, 

 and in places is consolidated into 

 level courses of rock from Cal- 

 careous infiltration.-^ 



Further to the west, at about the 

 middle of the Straits, near Tarifa, 

 another mass of sand is seen ex- 

 tending up the land to a height of 

 nearly 200 feet. I had not an op- 

 portunity of examining it except 

 at a distance, and it may be merely 

 Fig. 1 I f 1 Itar. blown sand ; but from its height 



S, San 11^ LI Bay. above the sea-level, I am inclined 



to attribute to it a similar origin to that of the stratified sands of 

 Catalan Bay. 



1 Mr. James Smith, of Jordan Hill, in his description of the geology of the rock (Quart. 

 Journ.Geol. Soc, vol. ii., page 41), records the occurrence oi Patella ferruijinea, a recent 

 Mediterranean species, at a height of 700 feet, and notices the evidences of old sea 



