54 



or there may elapse a considerable interval with deep erosion and some 

 sedimentation, so that between the flows are stratified leaf-bearing tuff- 

 beds and even conglomerates. Though of small thickness generally, 

 such deposits rise to a thickness of 100 ft. in Eraser's Gully, imme- 

 diately west of Dunedin. Rarely carbonaceous beds are seen, and a 

 single stratum of oil-shale is known. A series of small basalt-flows 

 poured out from scattered vents after the older volcanic rocks of the 

 region had been greatly eroded were the latest products of igneous 

 activity. 



The region now reached a mature state of erosion. The two 

 main valleys draining the volcanic hills ran in opposite directions, 

 their heads separated by a low divide. The region subsided beneath 

 the sea, the minor valleys all became deep embayments, and the 

 main divide was flooded over, so that a long through-channel was 

 formed the present Otago Harbour, the southern opening of which 

 was closed by the formation of the sandspit tying the Taieri Peninsula 

 to the mainland, where South Dunedin and St. Kilda now stand. 

 Sandbars also have very nearly closed entrances to the outer or 

 oceanward series of drowned embayments. The effects of a later 

 minor uplift can be recognized locally in the presence of raised 

 beaches and of two-cycle valley-forms seen in the Kaikorai Valley 

 (for example), west of Dunedin. 



W. N. BENSON. 



THE FLORA OF DUNEDIN. 



The. earliest settlers found the Dunedin district bush-clad from 

 the water's edge almost to the summits of the highest hills. Human 

 necessity has led to the clearing-away of much of this primeval 

 covering, but a wise foresight has set apart as a reserve a number 

 of forest, remnants, some even within the city. In these more or 

 less unmolested areas there has been preserved almost every species 

 of the primitive vegetation. 



The great variety of plant stations, resulting from an altitudinal 

 range of 3,000 ft. and a somewhat complex topography, is well 

 reflected in the diversity and number of species represented in the 

 district. Within a ten-mile radius there may be gathered over five 

 hundred species of flowering-plants and a still larger number of 

 cryptograms, exclusive of naturalized and other introduced species. 

 This list is inclusive of seventy-five ferns and one hundred and fifty 

 marine algae. Of the total assemblage, close on 90 per cent, still 

 exists in the area bounded by the visible horizon of the city. 



The great majority of the indigenous species are endemic, but the 

 same cannot be said of the genera, which are for the most part 

 Australian also. Indeed, only nine endemic genera are met with in 

 the neighbourhood of Dunedin. 



As elsewhere, the physiognomy of the forest is sombre, but far 

 from unattractive. The visitor is struck as much by the infinite 

 variety in the shades and hues of green of the New Zealand bush 

 as he is by the absence of green in the native-grass lands locally 

 represented on Flagstaff, Chain Hills, &c. Conspicuous blossoms are 

 the exception rather than the rule, most of the flowers being small 



