516 NOTES ON THE RECENT ERUPTIONS IN THE TAUPO ZONE, N.Z r 



Cape, extending inwards to a rather uniform distance of about 

 50 miles, and are flanked on both sides by volcanic tertiaries. The 

 formation, however, of the central portion which belongs to the 

 Maitai series of Dr. Hector, is, according to his determination, of 

 Lower Carboniferous character. They correspond consequently to 

 the rocks of the same or approximate period with which we are 

 familiar on the northern and southern flanks of our Upper 

 Carboniferous area, and though much more remains to be worked 

 out in both countries, the general conclusions at which Di\ 

 Hector has arrived are not likely to be much modified. (1) 



Now this S.E. coast range (known as the Rimutaka, Tararua,. 

 Ruahine and Kaimanawa ranges) in its run of over 300 miles 

 from Cook's Straits to East Cape, is flanked on its N.W. side by 

 a broad tract of country the original formation of which has 

 been completely broken up and obliterated by volcanic action, 

 and whose N.W. slope has been fractured ; dislocated and over- 

 whelmed on a gigantic scale. For the characteristic Maitai 

 rocks do not reappear except in small isolated scraps until they 

 emerge as ranges or parallel folds with a N.N.W. trend, starting 

 from a line running N.E. from Aotea. The bearing of these 

 ridges, which flank the Middle Waikato and the Thames, is 

 therefore inclined at an obtuse angle to the original strike of the 

 S.E. range. 



All the intervening ground is covered with the results of 

 volcanic action. In the first place, from the Bay of Plenty to 

 the Bay of Wanganui there stretches N.W. of the Ruahine 

 Ranges a long and comparatively narrow valley, the general floor 

 of which is formed of volcanic ejecta, mainly pumice, arranged in 

 gradually sloping plains or successive terraces. The highest point 

 or transverse watershed of this valley is marked by the twin 

 giants Ruapehu, an extinct volcano over 10,000 feet in height, and 

 covered with perpetual snow and glaciers, and Tongariro, which 



(1) The chief and most characteristic fossils of the Maitai series are 

 Spirifera bisulcata, Produces brcwhythertis,Cyathophyllum, and Cyathocrimts. 

 (Hector, Handbook, N. Z., 1879, p. 26), and these are also enumerated 

 among the Lower Carboniferous fossils of N. S. W. (Wilkinson's Report, 

 &c, 1882.) 



