524 A. C. KAMSAY ANJJ J. GEIKIE OK 



stone has been cut through by the engineering operations at the 

 galleries, and is well seen in section. The shelf slopes gently out- 

 wards, and is covered by a thick mass of limestone- agglomerate, 

 which also forms the slopes extending upwards to the base of the 

 limestone cliffs above. Underneath the agglomerate occurs a thin 

 stratum of well water-worn pebbly limestone-conglomerate. This 

 shelf is about 150 feet or thereabout above the sea, and is most 

 likely of the same date as the Europa Plateau. There are probably 

 other old sea-levels concealed beneath agglomerate along the face of 

 the Eock, both above and below Prince's Lines, the King's and 

 Queen's Lines appearing to occupy the site of an old sea-beach, 

 which has been scarped and otherwise modified for the purposes of 

 defence ; and donbtless low-lying old beaches might at one time 

 have been traced along the whole western side of the promontory ; 

 but the ground has been so much built upon and otherwise tampered 

 with that it is not possible now to map them out. 



One of the best-marked sea-levels on the Eock is that of Wind- 

 mill-Hill Plats (see Section VI.). This extensive plateau lies imme- 

 diately north of the Europa Plateau. It measures about 830 yards 

 in length, and has an average breadth of more than 330 yards, and 

 its surface is 370 feet or so above the sea. Bare limestone, with a 

 rough honeycombed surface, shows everywhere all over it, and we 

 saw no trace of any modern marine deposits. But the plateau has 

 been a good deal interfered with, and its inequalities removed so as 

 to make it comparatively smooth. It is quite possible, therefore, 

 that patches of sandstone, like those which were formerly well seen 

 upon the Europa Plats, may also at one time have been visible on 

 the Windmill-Hill Plateau. The platean is cut off on all sides, save 

 the north, by steep cliffs and precipitous slopes. In the front of 

 these cliffs, at the height of 170 feet above the sea, there was once 

 visible, according to Mr. Smith, an oyster-bed ; " and in the same 

 cliff, but 94 feet higher, in scarping the rock, there was discovered," 

 he tells us, " another recent shelly deposit." 



The high cliff which overlooks the Alameda Gardens (see Section 

 III.) probably indicates an old line of coast ; the slopes below it, 

 however, are, for the most part, thickly covered with agglomerate, 

 and so we cannot point to any marine deposits in proof of our con- 

 jecture. The base of this cliff is 500 feet above the sea. 



Some reference has already been made to the fact that the great 

 agglomerate of Buena Vista bears evident marks of having been sub- 

 jected to extreme denudation. It has been eaten into, as we have 

 seen, in the same manner as the limestone itself, and fissures and 

 winding galleries have been licked out of it — the rugged defile that 

 extends in a southerly direction from the top of Hospital Hill Eoad 

 towards the quarry at Little Bay strongly resembling a cave the roof 

 of which has subsequently fallen in. That this defile may have been 

 partly eroded by the action of the sea is also very probable ; and 

 there are certain isolated pinnacles and irregular columns of agglo- 

 merate in its immediate neighbourhood which have all the appear- 

 ance of being old sea-stacks. Similar stacks of the same rock mav 



