196 



was empty. If so, the lake must be very shallow, and the 

 year referred to must have followed a succession of droughts 

 in the main intake areas of the sub-artesian basin. 



The subsidence here has been very great, but subsequent 

 land-slipping has partly obliterated the abruptness of the 

 slopes, except on the south, where the great buttress of Tower 

 Point rises, now the highest point of the Mount. On this 

 southern wall there is an excellent exposure of the stratified 

 tuffs overlying the limestone, and along the western wall, low 

 in the depression, there is an exposure of rop} 7 lava pre- 

 viously described. The lumpy, land-slipped slopes, on the 

 north and west, are now clothed with dense bracken fern. 



North-west of Crater Lake, a single peak called the 

 Sugarloaf, stands high above the rest of the wall. It is 

 interesting from the regularity of its structure, in the shaping 

 of which erosion has played but a small part. To the west, it- 

 slopes " steeply down to the Moorak depression, and to the 

 east its face is formed by the collapse of the crater area. On 

 the other two sides, crescent-shaped depressions of the crater 

 wall have occurred, leaving the Sugarloaf standing like a 

 four-sided pyramid (see fig. 1). 



(f) The Moorak Depression. — The most western of the 

 subsided areas is small, but interesting. It is flat-bottomed 

 and not deep enough to contain water. It is noted in maps, 

 but has not been remarked by previous investigators. On 

 the north it is bounded by a long gently-sloping ridge, and 

 as one approaches the depression over this ridge, coming 

 from the town, the impression of its being the remnant of 

 a concentric outer wall of an older crater is quite distinct. 

 Other evidence does not support this idea, but this curious 

 depression well merits closer investigation. 



The ridge which bounds this depression on the north- 

 west is partly cut through, giving an excellent exposure of 

 the ash-beds ; these beds closely follow the contour of the 

 ridge, and suggest that the subsidence existed prior to the 

 conclusion of the explosive activity. There is an old well 

 in the flat-bottomed depression, but this is now partly filled 

 in. Possibly this is the well referred to by the late Professor 

 Tate in his class lectures as having been sunk 40 ft. through 

 stratified ash. 



The Moorak Station homestead stands on the bank of this 

 depression, which is therefore here referred to as the "Moorak 

 depression." It has been utilized as a rifle range, for which 

 purpose it is eminently suited, being sufficiently extensive, 

 quite level-floored, safe, secluded, and picturesque. 



(g) The Punch -bowl.— This, symmetrical, funnel-shaped 

 depression is in the southern wall of the Mount, south of 



