Uttley. — Tertiary Geology, Wharekuri to Otiahe River. 161 



the Maitai rocks, which at this point rise very steeply. From the green- 

 sands the following forms were obtained : — 



Corbula canaliculata Hutt. Polinices gibbosus (Hutt.) 



Cucullaea sp. Ostrea sp. 



*Limopsis aurita (Brocchi) Turritella caver shamensis Harris 



Panope orbita Hutt. 



Corals similar to the genera collected on the south bank of the Waitaki 

 River also occur here. - - 



. Marshall (1915, p. 381) obtained several species from these greensands at 

 an horizon lying 20.ft. above the quartz-grits. This writer recognized the 

 fault in this locality, and traced the fault-breccia towards Wharekuri, and 

 there can be no doubt that this fault is a continuation of that described 

 above at Wharekuri. 



(3.) Awakino Basin. 



Traces of the quartz-grits are seen in many places in the basins of the 

 Awahokomo and Little Awakino Streams. In the basin of the latter, about 

 a mile and a half from the main road, these rocks are exposed on the right 

 and left banks, and to the south-west the eroded surface of the Maitai rocks 

 rises from beneath them, and slopes gently upwards towards the crest of 

 Kurow Hill. The quartz-grits evidently formerly covered the whole of this 

 " fossil plain," which has now been partially stripped of its former cover. 

 The plain forms the back slope of the tilted block figured by Cotton (1917b, 

 p. 432). This block will be referred to later as the Awakino tilted block. 

 Quartz-grits and greensands occur as mapped in several places in a south- 

 westerly direction towards the Big Awakino River, and in many places close 

 to the line of the Wharekuri-Otekaike fault, where the Maitai rocks rise very 

 abruptly. A mile west of the trigonometrical station on Kurow Hill there 

 is a small coal-mine, which supplies an inferior type of coal. It is being 

 worked at present close up to the face of a steeply rising greywacke scarp. 

 The coal-rocks dip away from the scarp at 45° in a direction S. 28° W. 

 The scarp, which is almost undissected in this locality, extends in a north- 

 westerly direction, gradually diminishing in height, and reaching the road- 

 level about half a mile north-west of the point where the west branch of 

 the Little Awakino crosses the road on the south-west side of Kurow Hill. 

 The scarp is evidently a fault-scarp, determined by a fault of diminishing 

 throw, which trends N. 60° W. to meet the main Wharekuri-Otekaike fault. 

 The fault botmds the Awakino tilted block on the south-west. In the angle 

 defined by these two faults the gravel deposits are of great thickness, but 

 the basal quartz-grits and overlying greensands (McKay, 1882b, p. 102) crop 

 out occasionally. The Tertiary rocks have evidently been extensively eroded, 

 and their remnants are buried by the gravel deposits, which now form hiUs 

 2,000 ft. in height [loc. cit., p. 99). Cuttings show that the gravels are of at 

 least two t}'p»es — heavy greywacke and sandstone boulder deposits, and 

 deposits composed of well-rormded sandstone pebbles and sands. At one 

 place on the road between the basin of the Little Awakino and the Big 

 Awakino the soft unctuous bluish clay similar to that described at Wharekuri 

 was observed in a cutting. McKay states that the latter (the so-called 

 " Pareora gravels ") are highly tilted in the present locality, and he refers 

 the coal deposits of the neighbourhood to the horizon of these rocks (1882b, 

 p. 102). The gravels extend to the Kurow River, forming even-topped 

 elongated ridges and pyramidal hills, which have been blocked out by the 

 action of the numerous intermittent streams that drain the area. Across 



6— Trans. 



