Thomson. — Geoloyy of Middle Clarence and F re Valley.-i. 317 



Clarence fault and its branches. Where on the upper side of the syncline 

 the sequence' is reversed, a small thickness of Clarentian beds lies above 

 the flint-beds, between them and the fault-line. These were observed in 

 the large tributary of the Ure Eiver entering it in a south-east direc- 

 tion from Blue Mountain. About 100 ft. of Clarentian beds are hpre 

 exposed, consisting of micaceous mudstones weathering purple-grey with 

 a yellow efflorescence on joint-planes. They have the same strike as 

 the underlying flint-beds — viz., north-east — with a dip of about 50° to the 

 north-west — i.e., towards the fault-line. A large concretion lying in the 

 creek at this point was observed to be crowded with fibrous fragments 

 of Inoceramus. There appears to be perfect conformity with the flint- 

 beds. The actual fault-line is obscured by slips. 



In a tributary of the above creek, entering if from the north-east 

 along the fault-line, some decomposed amygdaloidal basic volcanic rocks 

 were seen to the north-west of the flint-beds, and are therefore probably 

 in the Clarentian series. 



Middle Ure Valley. — Pebbly mudstones were observed in the Blue 

 Mountain Creek at the apparent top of a series of hard sandstones and 

 thin-bedded mudstones apparently overlying the Amuri limestone or Weka 

 Pass stone, which is here not more than 150 ft. thick, and strikes in 

 a north-easterly direction, dipping north-west. Probably the series is 

 overturned and the succession reversed at this point, as it is higher up 

 the Ure Valley. The conglomerates contain fragments of Inoceramus 

 and pebbles of dark limestone (itself containing Inoceramus), besides white 

 quartz and red jasper. A fault crosses the creek about two miles up, 

 and above this, in a branch running to the Blue Mountain, the Clarentian 

 rocks appear to be repeated. There is a succession of hard sandstones 

 with occasional shaly beds, both containing occasional plant fossils, and 

 thin pebbly mudstones containing Inoceramus fibres. There are many 

 repetitions of the pebbly mudstones in the creek. Many small dark fine- 

 grained dykes were observed intersecting the sandstones. 



Lower Ure Valley. — Clarentian rocks are probably well developed in 

 the hills to the north of the lower Ure, where thin bands of Amuri 

 limestone appear, but exposures are not good and the sequence has not 

 been clearly ascertained. Not far above the crossing of the coach-road 

 a syncline of limestone occurs, underlain by sandstones and mudstones 

 containing Inoceramus. The limestone crosses the hills obliquely and 

 terminates against the Awatere beds, probably in a fault-line, and the 

 beds farther up the hills to the west are therefore probably Clarentian. 

 They consist mainly of sandstones, but the top of Hungry Hill is com- 

 posed of volcanic breccia, which may be Clarentian. McKay correlates 

 it with the Flaxbourne breccias, which lie at the base of the Clarentian 

 series in the Ward district 



Mead River. — McKay describes the Clarentian rocks exposed in the 

 Mead River as follows : "In the Mead, the conglomerates at the base of 

 the Amuri series are finely exposed. The succeeding beds are grey sand- 

 stones and darker shales thrown into a great number of undulations, 

 which are flat and shallow, or more frequently sharply caught up at high 

 angles, and are often crushed and contorted in a most extraordinary 

 inanner. Here beds of this character continue without means of dis- 

 tinction upwards into the Waipara formation, and, scarcely altered in 

 character, reach to the under-surface of the great flint-beds that underlie 

 the Amuri limestone." 



