SMITH ON GIBRALTAR. 49 



on the east side of the rock, between high and low water, are per- 

 forated by Lithodomi, and covered with Balani and numerous clus- 

 ters of the rock mussel {Mytilus arcuatus). In the elevated deposit 

 the Balani were still adherent, the shells of the Pholades in their 

 holes, and the clusters of mussels in the most perfect state. These 

 fossils were found in a crevice, and their preservation is owing to a 

 thin coating of stalagmite. P>om the state of the shells, with both 

 valves adhering, the animals must have been alive when the ele- 

 vation took place : I infer therefore that it was instantaneous. 

 This deposit was discovered in a quarry at the North Front. In 

 scarping the ancient sea-cliff at Europa Point, a raised beach was 

 found at the height of 50 feet, and another 20 feet higher; in this 

 last the molar tooth of the fossil elephant was found with sea-shells 

 adhering to it : from these deposits I collected nearly 100 species, 

 all recent; the cliff in which they were found is about 80 feet high. 

 Above this is the extensive sea-worn plateau of the Europa Fiats ; 

 its surface is almost entirely composed of bare water-worn rock, but 

 there are notwithstanding patches of the indurated sand, in which I 

 found imbedded a valve of the Pecten maximus and other fragments 

 of shells. This plateau is backed by a second range of cliffs, in the 

 front of which, at the height of 170 feet above the sea, there is an 

 oyster-bed ; and in the same cliff, but 94< feet higher, in scarping the 

 rock, there was discovered another recent shelly deposit. On the 

 east side of the rock, just above the third Europa advance battery, 

 there is a bed of bivalves (Pectunculi)^ corresponding in height with 

 the oyster-bed ; and on the same side of the rock the hard modern 

 sandstone, already mentioned, occurs in beds of great thickness, 

 with occasional sea-shells, all recent. At the height of 600 feet I 

 found, as formerly noticed, a similar bed with recent shells. All the 

 deposits hitherto mentioned are in their natural position, and are 

 consequently newer than the upheavals attended by dislocation and 

 change of position. But although 600 feet is the highest point at 

 which we have the evidence of organic remains to prove these more 

 recent changes of level, yet, as the whole surface of the rock is sea- 

 worn, and I find no break in the continuity of the surface, and as 

 also many of the sea-worn caves, at much higher levels, are in their 

 natural position, I infer that the whole mountain up to its summit, 

 a height of 14-70 feet, has been submerged subsequently to the last 

 of the disturbances. 



We cannot account for the phaenomena which present themselves 

 without supposing movements of depression as well as of elevation ; 

 but such movements are always difficult of proof, because the sea 

 washes away and re-arranges the loose unconsolidated beds : hence 

 vegetable deposits, such as submarine and subterranean forests, are 

 exceptional cases of rare occurrence ; but where petrifaction has 

 taken place, the sea does not destroy the rocks. Beds formed of 

 vegetable soil and mud, and containing nothing but the remains of 

 land animals, converted into breccia by calcareous water, must have 

 been formed on land ; and as we find at Gibraltar such bods i)assing 

 under the sea, we must admit a depression of the land since they 



VOL. II. — PART I. li 



