1867.] HAAST CANTERBTJRY, NEW ZEALAND. 345 



On the eastern side of the Southern Alps, and unconformably over- 

 lying the older Palaeozoic strata, occur two fossihferous beds, of which 

 one occurs in the Clent hills, the other being situated ten miles north 

 of it, on the western slope of Mount Potts, of which the Mount Guy 

 range is a continuation. 



The latter, which I named the Spirifer-beds, are, according to 

 Prof. M^Coy, of Melbourne, either Upper Devonian or Lower Carboni- 

 ferous. They are situated near the junction of the main branches 

 forming the river Rangitata, and consist of indurated shales, clay- 

 slates, and coarse sandstones. One of the commonest fossils is Spi- 

 rifer Uneatus, M'Coy, which occurs in great masses ; besides it, 

 some other Spirifers are represented, as, for instance, S. duodecim- 

 costatus and latus, — also the genera Productus, Orthis, Murchisonia, 

 and some others. 



The Clent-hiU beds consist mostly of shales and conglomerates, 

 the latter made up of pebbles of plutonic, metamorphic, and trappean 

 rocks, of every possible variety, many of which have disappeared 

 from the surface of New Zealand. In fact, a complete Museum of 

 the former crust of the earth is here presented to us. In the shales 

 of these beds numerous beautiful impressions of plants occur, mostly 

 ferns and belonging to the genera Pecojjteris, SpTienopteris, Camp- 

 topteris, and Tceniopteris ; a few of them are identical with Austra- 

 lian forms, as for instance the Tceniopteris Daintreei, M'Coy, to which 

 that distinguished palaeontologist assigns a Jurassic age. 



The Southern Alps proper are bounded on their eastern side by a 

 belt of old Tertiary volcanic rocks, quartzose trachytes, and pearl- 

 stones, which have without doubt risen in a semifluid state in longi- 

 tudinal fissures ; they form generally dome- shaped mountains, some 

 of them 4000 to 5000* feet high ; but nowhere is the least sign of a 

 crater or lava-stream discernible. 



The trachyte zone surrounds Banks peninsula as the segment of a 

 circle, distant from it about 50 miles, in a direction east and west, 

 but only approaching the seashore, north and south, at a distance of 

 100 miles. 



Thus the great foldings of the Southern Alps proper are bounded on 

 both sides by igneous rocks, which circumstance may account in some 

 degree for the steepness of the folds throughout the whole region. 

 At the same time the difference of age and composition of these igneous 

 zones on both sides, the granites on the western and the trachytes 

 on the eastern flanks, may lead us to conclude that the great anti- 

 clinal and synclinal arrangements did not take place simultaneously, 

 but that its western portion was formed when, at the beginning 

 of the Tertiary period, deep-seated disturbances began to occur 

 on its eastern side, by which the strata were brought into their 

 present position. Longitudinal fissures were at the same time opened, 

 through which the volcanic rocks made their appearance. 



On these, the oldest volcanic rocks in the Province, repose our 

 Tertiary series, beginning with extensive agglomeratic and tufaceous 

 deposits, made up from the disintegration and destruction of trachyte 

 rocks, followed by argillaceous beds and sands, with lignite-seams 



