426 Tranmciions. — Geology. 



full of bivalve shells, a Kellia predominating. In the bed of 

 the river near the bridge is an excellent section showing the 

 fossiliferous clays resting on the slates, which for the first time 

 make their appearance in this direction, although some distance 

 above and below the bridge the slates are the only rocks 

 exposed on either bank of the river. I remember that a 

 similar section, showing clay and sands resting on the slates, 

 is met with in the right bank of the Tukituki Eiver at a place 

 know^n as the Khyber Pass, on the flanks of the Euahine 

 Mountains. There the slates and blue clay-sands meet, the 

 latter at their junction with the slates presenting the appear- 

 ance of the bow^ of a boat. On the right bank of the Ngaruroro, 

 at Kuri]3apanga, large deposits of pumice are found for at least 

 200ft. above the river, and there are no traces whatever of the 

 blue clay-sands in this direction. The high hills between 

 Kuripapanga and Ohai;ko scarcely change in their rock- 

 characters the whole way, except that on the former side of 

 the hills tJie slates show cleavage-structure, whilst on the 

 Ohauko side they seemingly run into sandstones and present 

 the appearance of having been affected by igneous agencies. 

 Traces of pumice are to be met with over all the hills in this 

 direction, and in places where pockets have been formed it is 

 many feet in depth. About midway between Kuripapanga 

 and what is known as the Taruarau Spur the blue clays 

 reappear, and are overtopped here and there by bands of 

 lenticular limestones. These clays and limestones cover a 

 large part, so it would seem, of the Ohauko plateau ; but the 

 pumice which covers the surface diminishes greatly tlie value 

 of what otherwise would be a rich district. The clavs are 

 fossiliferous, but the limestones, though composed mainly of 

 broken sliells, do not provide any specimens which it is possible 

 to identify with certainty. As the road leads into the Tarua- 

 rau Eiver the pumice-terraces reappear, and the}' overlie the 

 marls on the left bank and the slates on the i-ight just as 

 they do at Kuripapanga. On the latter bank the pumice is 

 very deep, and large trees of charcoal, with branches and 

 roots intact in some cases, are exposed in the pumice, and 

 present an appearance as if a forest had been suddenly sub- 

 merged by a vast deposit of hot pumice, and ignition had taken 

 place as it does in the ordinary process of charcoal-manu- 

 facture. As at Kmipapanga, there is no trace of marls or 

 limestones on the right bank of the river ; nor do these rocks 

 again appear until towards the top of the ascent of the Tarua- 

 rau Spur, where several blocks of limestone are seen at a 

 height of about 2,G0Oft., or about 450ft. below the top of the 

 hill known as Otupi. OnOtupithe rocks resemble those which 

 flank the western side of the Kuripapanga Eange, except that 

 they are harder and of a somewhat deeper blue. When 



