76 Geological Society :— 
by clay-slate, igneous rocks, and at one spot on the south by creta- 
ceous strata; and it is dotted by upwards of sixty extinct volcanos, 
often closely situated, and showing in nearly every instance a well- 
defined point of eruption, generally a cup-like crater, on a hill about 
300 feet high. Interesting instances of successive volcanic eruption 
are numerous all over this district, 60 miles round Auckland; and 
there seems to have been four distinct epochs of eruption, thus 
classified by Mr. Heaphy :—1. The first was that which raised the 
trachytic mountains and the black boulder-like igneous rock. 
2. Then came the eruptions in the Tertiary period, the ashes 
of which form beds in the Tertiary rock. 38. Then the eruptions on 
the upheaval of the Tertiary cliffs: these appear as cones above 
faults on the Tertiary beds and on the edges of cliffs. 4. Lastly 
the eruptions that have broken through the ‘Tertiary beds, and the 
lava-streams of which follow the natural valleys of the country. 
The volcanic phenomena were illustrated by maps and numerous 
sketches by the author. Some Tertiary Terebratule, some few 
fossil plants, and some Cretaceous fossils (Jnoceramus and Belem- 
nitella) accompanied this memoir. 
3. ‘©On the Geology of a part of South Australia.” By T. Burr, 
Esq. From the Colonial Office. 1848. 
The lowlands about Adelaide on the west, and along the River 
Murray on the east, consist of horizontal beds of limestone and cal- 
careo-siliceous deposits, yellowish and reddish in colour, full of 
marine fossils, and of the Tertiary age. Sometimes gypsum and 
ferruginous sand replace the limestone. These plains are arid, 
except where granite protrudes from the surface, presenting cavities 
in which rain-water collects. The author observed a similar Tertiary 
formation on Yorke’s Peninsula, at Port Lincoln, and to the 8.E. to 
beyond Rivoli Bay ; and it probably forms vast tracts in New South 
Wales and Western Australia. None of these tertiary districts 
appear to exceed an elevation of 300 feet above the sea. 
In describing two volcanos in South Australia, Mount Gambier 
and Mount Schauck, Mr. Burr remarked that, coming from the west 
or north-west, at about 20 miles from these hills a white coral-lime- 
stone (Bryozoan limestone) containing flint or chert, takes the place 
of the limestones and calcareous sandstones, with recent sand-forma- 
tion, previously passed over. This white limestone is remarkable 
for the numerous deep well-like water-holes in it, within about 12 
miles of the volcanic mountains and about east or west of them. 
Mount Gambier has a height of 900 feet above the sea (600 feet 
above the plain), and has three craters, lying nearly east and west, 
and occupied with lakes of fresh water. Mount Schauck, at a distance 
of about 9 miles, magnetic south, is circular, and has one large, and 
two small lateral craters. 
The author next described the granite, gneiss, and slaty rocks 
along a section extending from the River Murray and Kangaroo 
Range, across Mount Barker and Mount Lofty, towards Adelaide ; 
and noticed the mode of occurrence of the ores of copper, iron, lead, 
&c. in these rocks. Lastly he noticed and explained the occurrence 
