Valley to Ahaura River is mapped as lower sub-schist. Rocks of this belt were examined at the mouth of Waikiti River, in the upper Haupiri River, and at Taramakau River.

Content. The rocks consist of alternating bands of sandstone, siltstone, and mudstone, similar to those in the overlying belts. The increased rank of this belt is shown by an increase in silicification. The sandstone bands look massive and are extremely hard, the finer bands are more “flinty” than are corresponding beds in the upper belts. Contortion (“pinch” and “swell”) of the bedding is characteristic. Quartz veins are abundant in the sandstone bands in the upper part, and in both the sandstone and mudstone bands in the lower part. None of the beds are cleaved.

A photo of a boulder from the lower part of this belt is illustrated by fig. 9. The rock consists of one to three inch bands of sandstone and darker siltstone. The beds are complexly deformed, minor puckers being superimposed on folds with a wave length of about six inches. Two sets of quartz veins are conspicuous—thin laminae that follow the bedding and thicker veins controlled by the fold axes. Other veins lie in different directions and show no obvious relation to the fabric of the rock. Many of the thin quartz veins are much more strongly sinuous than the bedding, and if these veins were considered alone they would give an erroneous idea of the degree of folding. Evidently the fabric of the rock controlled the formation of the quartz veins, the axes of the sinuosities being in the direction of the incipient linear schistosity.

Large boulders of conglomerate were found in a small stream on the north side of Taramakau River, three miles upstream from the mouth of Otira River. They probably belong to about the middle of this belt, as they are associated with rocks of lower sub-schist rank in the stream. No conglomerate was found in the streams draining the belt to the north. None of the conglomerate pebbles have been stretched, but a few have been broken by pressure. The joints pass through matrix and pebbles alike. The matrix is welded to the pebbles to the same degree for each pebble. Most of the matrix can be separated without difficulty, but parts cannot be detached without breaking off the surface of the pebbles. No quartz veins were seen penetrating the conglomerate, but they are not uncommon in siltstone boulders in the same stream. The most striking feature is the apparent absence of pebbles of greywacke or of vein quartz, rock types equally as resistant as those represented and usually far more common. About a third of the pebbles are sedimentary, a third igneous, and the remainder too fine-grained for macroscopic determination. The igneous pebbles are pink, finegrained, somewhat gneissic, biotite granites ranging up to six inches and averaging one inch in diameter. They are better rounded and more spheroidal than the sedimentary pebbles. Two sedimentary types are represented—quartzites and siliceous limestones. Quartzite pebbles are the more numerous, and range from near white to medium grey in colour and up to three inches in diameter. About half are slightly calcareous and a few are veined with calcite. Siliceous limestone is less abundant and the fragments, on the average, smaller. The largest limestone pebble is flat, extremely siliceous, veined with calcite, and light brown-grey in colour. Smaller limestone fragments show up in the matrix with acid. No fossil traces were seen in either the limestone or the quartzite.

The pebbles represent resistant rock types and cannot be considered representative of the rocks of the area of origin, of which they may represent only a minor part. In New Zealand similar quartzites, calcareous quartzites, and