446 Transactions. — Geology. 



elevation of 2,000ft., together with the greater extent of 

 land then existing, but since removed by ice erosion, would 

 be sufficient to extend the glaciers to their former limits. 



I will now proceed to describe some morainic mounds 

 which I discovered last June in the Leith Valley, near the 

 foot of Waikari. These moraines are situated near the top of 

 the ridge separating the Leith Valley and Boss's Creek, which 

 flows into the city reservoir. They extend from the saddle 

 between the Leith Valley and Eoss's Creek southward, run- 

 ning parallel with the Leith Valley and terminating in Mr. 

 Henry Skey's farm, Section No. 74, at a point nearly due 

 north of the upper reservoir. Although near the top of the 

 ridge, they lie on the fall into the Leith. There are two 

 lines of mounds parallel to each other. The upper mound, 

 about 500 ft. above the sea, begins inside Mr. Skey's bound- 

 ary, crosses the road, and runs in a west-north-west to east- 

 south-east direction for about 5 chains, gradually increas- 

 ing in height towards the saddle until it suddenly ends in a 

 pile of andesitic rocks. At a point about half its length it 

 is 8 ft. high, presenting a steep face to the south and a long 

 gentle slope to the Leith Valley. Numerous tree- stumps and 

 clumps of native forest around the saddle indicate that the 

 whole ridge was at one time covered with forest. At the 

 present time a rimu (Dacrydium cupressinum), 4 ft. in circum- 

 ference and 50 ft. high, is growing in the depression of the 

 lower mound. The lower mound resembles a line of massive 

 earthwork constructed for defensive purposes. It is cut 

 through by a road, and is seen to be composed, at that point, 

 of fragments of rotten rock now forming compact yellow clays. 

 The composition of this mound is also seen in a recent 

 cutting, 10 ft. long and 4 ft. deep, near its western end and on 

 its lower slope, which exposes a confused mass of andesitic 

 rocks and clay. The rocks are mostly angular, tabular in 

 form, and often of enormous size. The pile of tumbled rocks 

 at the western end of the upper morainic mound was evidently 

 exposed by the removal of the associated clays by recent 

 denudation. 



The high-level terraces in the valley of the Leith and the 

 alluvia west of the saddle would tend to show that the Leith, 

 before the excavation of the present rocky gorge, flowed across 

 Eoss's Saddle to the back of Maori Hill, and thence westward 

 in the direction of the present Kaikorai Valley. The present 

 deep narrow valley of the Leith, with its precipitous rocky 

 sides, was obviously excavated in comparatively recent times. 



