THE GEOLOGY OF GIBRALTAR. 511 



Further west, in Camp Bay, the shale with thin beds of limestone 

 and grit dips under the great mass of limestone in an abnormal 

 manner, its natural position being above that rock, as shown in the 

 same section at "Windmill-Hill Barracks, and in Sections Nos. I., II., 

 III., and IV. 



Section No. VI. shows a somewhat similar arrangement of the 

 strata on the eastern side of the main fault at and near the battery 

 above the cliff at Europa Advance Road; the limestone beds stand ver- 

 tically, overlain in part by agglomerate, and on the southern side of 

 the fault the strata dip easterly at angles varying from 32° to 80°. 



Section No. VII., across Europa Flats, shows the same easterly dip 

 of the limestone. 



Notes on adjacent tracts list Spain and on the opposite 

 African coast. 



The sandy plain that lies between the North Front and the Sierra 

 de Carbonera is about 2 miles in length and more than 1000 yards 

 wide south of the British lines, rather more than a mile wide at 

 Linea, and somewhat more than 2 miles wide from east to west at 

 Pachon. Between the Eock and the ground around Linea the 

 country is nearly flat, having an average height of about 10 feet 

 above the level of the sea. Further north, towards the Spanish 

 hills, this average elevation is varied by the occurrence of low dunes 

 of blown sand. 



North of this plain there rises the hilly ground of the Sierra 

 de Carbonera, the Queen of Spain's Chair, 971 feet in height, 

 forming a prominent point in the landscape. From the neighbour- 

 hood of the " First Tower," on the east, to the Biver Lavo and the 

 mouth of the Guadaranque, the rocks consist chiefly of beds of 

 sandstone and shale, with limestone at one place, the sandstones, on 

 the whole, predominating. The prevalent dips are south-west and 

 west ; but occasionally the beds dip easterly, as shown in the ground 

 in places between Pachon and the Queen of Spain's Chair. East of 

 Pachon, however, the sandstone strata north of the sandy plain 

 seem for a small space to dip to the south. The alternating strata 

 of sandstone and shale of the coast of the Bay of Gibraltar are well 

 seen on the shore at low tide, at and near Punta Mala and at 

 Rocadillo Tower, where the strike of these beds trends more or less 

 towards the shaly ground that overlies the limestone rock of 

 Gibraltar. 



South of the wide alluvial plains and sandy hills of Guadaranque 

 and Palmones, the strata between Punta del Beconcillo, Algeciras, 

 and Sandy Bay consist chiefly of red, green, yellow, and grey clays, 

 shales, and marls with ribs, bands, and beds of sandstone and mud- 

 stone, some of the intercalated sandstone bands being somewhat 

 calcareous, as at Almirante Tower. The same kinds of strata of 

 shale and sandstone form the interior of the country west of 

 Algeciras, as far as the waterfall on the river Miel, and apparently 

 much further. 



The general strike of the beds along the north coast of Gibraltar 

 Q. J. G. S. No. 135. 2 u 



