148 Hutton^ Physical Geology of Malta. 



on which Torre Hamra is situated. It is on this terrace, about a 

 mile west of Torre Hamra, that the Maghlec Caves were found 

 (Plate IX. Fig. VII.). Behind the Tower the ground again rises, 

 until it attains a height of 400 feet. 



No other great faults are known in this part of the Island, but 

 round Valetta, and perhaps in other places, numerous small faults, 

 with throws of a few feet only, occur in the Freestone ; a few 

 of the largest of these extend down into the Lower Limestone, 

 but most do not. In a low sea-cliff near Eort Tigne, six faults, 

 with throws of from 1\ to 4 feet, occur within a distance of 

 90 yards (Plate IX. Fig. IX.). A thin dark band, composed 

 apparently of the remains of marine Algse, runs through the 

 cliif about half-way up, and enables these throws to be accurately 

 measured. None of these faults penetrate the Lower Limestone, 

 the top of which is exposed at the sea-level ; it is therefore 

 evident that they were not produced by movements from below, 

 it is also certain that they could not have been caused by lateral 

 pressure, for in that case the throws of the faults would all have 

 been reversed ; nothing therefore remains to account for them but 

 pressure from above, and this I believe to have been the cause. 

 I suppose that the rock, being already jointed, was pressed down 

 before it was quite hard, by the weight of the superincumbent 

 strata, and the pressure on each fragment being proportional to the 

 area of its upper surface, those fragments which had the largest 

 upper surface in proportion to their bulk were more compressed 

 than the others, thus forming the faults. The broken state of many 

 of the fossils, particularly the Echini, in this bed, is a proof that it 

 has undergone considerable compression. 



I may, perhaps, here mention that I consider that all cases of 

 " reversed faults " will be found to have been caused by lateral 

 pressure. 



North of the main fau.lt the land is much lower than on the south 

 side. This is due partly to the throw of the fault, and partly to the 

 fact that the Upper Limestone on this side has undergone a greater 

 amount of denudation. Along the line of fault, and at various 

 other places on the Upper Limestone, such as Fomm-er-rih and 

 Toffiha, patches of the Elephant-bed are found, generally filling 

 up hollows. This part of the Island is again crossed by two faults 

 on each side of Melleha Bay, which, running parellel to the main 

 fault, have let down the land between them, so as to form the 

 valley and Bay of Melleha (see Plate VIII., Figs. I. 11. and III.). 

 The fault south of the bay has a throw of 100 feet; that on the 

 north, 150 feet. 



North of Melleha Bay, the beds dip due north in a more marked 

 degree than in any other part of the Island. 



The general dip of the strata, between Melleha Bay and the 

 main fault, is very slightly to the west; but on the south-west 

 coast the beds have been compressed into one or two undulations, 

 which are not found on the north-east coast. These undulations 

 appear to have been caused by the lateral pressure exerted when 



