424 Transactions. — Geology. 



chain of the Euahine Mountains to appear through what was 

 at the time a Hmestone country, extending from the east to the 

 west coast. At the time when this elevation was in progress, 

 denudation was great, and the fractured hmestones were 

 much worn by the shattered and indurated slates, which had 

 probably been subjected not merely to great pressure, but also 

 to heat-zones, such as might be expected at the beginning and 

 during the progress of the volcanic period which caused such 

 marked and extensive changes in the physical aspects of the 

 North Island. These limestones correspond, and, in fact, are 

 identical, with the Maunga-haruru limestones as seen so well 

 exposed in the great scarp at Te Waka, on the Taupo road 

 overlooking Pohui. They have, however, been so worn, and 

 ground, and powdered within the area under notice that 

 only in isolated spots one sees — just as one sees on the flanks 

 of the Whakarare Mountains, in the Kereru district, further 

 south — the remnants of an extensive limestone range, of 

 wliich few traces remain, so great was the denudation which 

 succeeded the earth's movements referred to above. In the 

 Otaharuru Creek, at Glenross, near the fellmongery of Mr. 

 Williams, lenticular limestones appear, interbedded with the 

 blue clays and clay sands, as seen near the crossing. Terc- 

 bratula, Ostrea, and Anomia '&]ie\\^ are common, and in several 

 places broken portions of Pinna shells were also numerous. 



From this place the road passes over the hills to Mount 

 Blowhard. Many of the exposures by the way show limestones, 

 but as the top of the range is reached fossiliferous sandstones 

 appear. The sandstones over a large extent of the elevated 

 country have comparatively recently become quite denuded of 

 vegetation, the fires which raged over the country for the 

 destruction of fern and scrub having destroyed all the roots 

 which bound the soil to the decomposing rocks. The bared 

 sandstones provide an excellent collecting-ground for fossils, 

 as in many places they are crowded with specimens of coral 

 in an excellent state of preservation. 



At a spot where the road passes the joining saddle of 

 the range some very remarkable limestones appear. They 

 resemble a series of organ-pipes, are fluted like thern, and 

 arranged in columns and tiers as in an immense organ- 

 chamber, presenting a very grand and imposing appear- 

 ance, the concave and convex flutings being exceedingly 

 perfect. These flutings have no doubt been caused by 

 chemical and aerial agencies : it seems to me, however, 

 somewhat difficult to account for the perfection of so many 

 hundreds of flutings, with such regular concave and convex 

 surfaces, by chemical means alone, as in texture the lime- 

 stones to all appearance were the same, and the concave 

 and convex surfaces appeared equally hard. 



