Uttlet. — Tertiary Geology, Otiake Biver to Duntroon. 143 



two limestone horizons in North Otago, separated by the Hutchinson 

 Quarry and Awamoan beds The lower limestone he called the Oamaru 

 stone, and the upper limestone the Waitaki stone, as it was strongly 

 developed in the Waitaki Valley. The Maruwenua limestone and the 

 Otekaike limestone at Wharekuri were considered to be at the same 

 horizon above the Awamoan, which, it may be remarked, is an altogether 

 difierent view from that which McKay held in regard to the relationship 

 of the Ototara (Maruwenua) limestone and the Otekaike limestone. McKay 

 certainly considered the two limestones distinct rocks ; but the require- 

 ments of the Cretaceo-Tertiary theory demanded this, as a break had to 

 occur somewhere in the series. Never did McKay dream of placing the 

 Waitaki limestone above the Hutchinsonian and Awamoan horizons, for 

 he always maintained the infra-position of the limestone in North Otago 

 and South Canterbury (1882a, p. 65, and 1882b, p. 103). Park correlated 

 the greensands at Wharekuri with the Hutchinson Quarry beds at Kakanui 

 (1905, p. 523), but McKay had always maintained that the beds above the 

 limestone in the Wharekuri area were undoubtedly the representatives 

 of the Hutchinson Quarry beds at Oamaru. Park placed the coal-beds at 

 Wharekuri at the base of the Tertiary series. 



Marshall, Speight, and Cotton (1911, p. 405) stated that there was no 

 evidence' that the greensands lying beneath the Maruwenua limestone are 

 the equivalent of the Hutchinson Quarry beds at Oamaru, but agreed with 

 Park in his contention that the series is conformable. ■ 



Marshall (1915, p. 383) gave a list of fossils from the fossiliferous beds 

 at Otiake, and referred them to the horizon of the Oamaru limestone 

 (Ototaran). 



Cotton (1917a, p. 285, and 1917b, p. 432) showed that the Waitaki 

 River followed a complex graben along the northern boundary of the 

 block-complex which forms the mountains of Otago, and he described several 

 interesting examples of tectonic forms. 



IV. Description op the Tertiary Beds. 



» 



(1.) Trig. Station Z, Otiake River. 

 The exposure of fossiliferous beds in this locality is seen on the face of 

 a rather prominent clifE, near the Trig. Station Z, close to the Otiake River, 

 and about a mile above the railway bridge. The beds dip 7° in a direction 

 N. 20° W. The section exposed here is illustrated in fig. 2. 



Fig. 2. — -Section at Trig. Station Z, Otialce River, (a) Otekaike limestone ; (6) glau- 

 conitic calcareous bands ; (c) less glauconitic calcareous sandstonesj with 

 glauconitic bands passing up into {d) ; {d) softer calcareous mudstone. 



The lowest bed (a) is a compact light-yellowish-brown limestone (Otekaike 

 limestone) containing abundant tests of. Foraminifera, a small quantity of 

 clear subangular minute grains of quartz, and some glauconitic casts of 

 Foraminifera. Microscopic fossils are scattered through the mass of the 

 rock. Pachymagas huttoni Thomson, Pecten huttoni (Park), Limopsis aurita 

 (Brocchi), Dentalium solidum. Hutt., Cucullaea sp. were found in the lime- 

 stone. The overlying bed (b) is distinctly marked out from the underlying 



