C—ll

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older date. Some of the higher terrace-flats on the north-west side of the Aorere, opposite the Quartz Ranges, should rightly be referred to this series, and by Mr. Park they are regarded as Pleistocene, but with the same he includes the old high-level gravels capping the coastward hills between Collingwood and Parapara. These latter are distinct, and have to be regarded as of Pliocene age. Neither does he make any distinction between the low-lying gravels along the banks of the river and those on the Quartz Ranges at 1,700 ft. above sea-level, and which there are faulted and involved amongst the older rocks. Mr. Park also maps the auriferous quartz-gravels of Golden Gully, Lightband's Gully, Appo's Flat, &c, as being Pleistocene, and in age not different from the beds that interpose between them and the quartz-gravels—viz., the marly clays, and shelly or compact limestones of Miocene and Cretaceo-tertiary age. There are, on the middle part of the slope leading up to the Quartz Ranges, gravels that would correspond with those on the opposite side of the valley, as also would the terraces on the eastern side of Druggan's Flat, below the junction of the Slate River. There are also high-level terraces along the valley of the Slate River that may properly be referred to as Pleistocene. lll.—Pliocene. The Pliocene strata of the district, according to the views here expressed, constitutes a double series of gravels, of which the younger consists of very coarse gravel-conglomerates that, from the Township of Collingwood, stretch along the coast-line and cap the coastward hills to Parapara Inlet, and thence, bending more to the west, they terminate as a continuous deposit on the north-east side of Appo's Creek, below Appo's Flat. The same beds, or conglomerate gravel-deposits that may be referred to the same age, are found between Appo's Creek and the Slate River, and further to the south-west beyond the Slate River. On Red Hill Ridge these gravels are found along the line of track to Golden Gully. Along this line they occur as outlying patches up to 1,200 ft. above the sea. I have not visited The Castles on the Rocky River. Auriferous gravels are there present at the eastern foot of the limestone cliffs, and these have by Mr. Park been referred to the Pleistocene. This can barely be the case, and, unless they belong to a horizon under the limestone, they must be regarded as Pliocene deposits. 1 gathered the information from miners in the district that at The Castles auriferous-quartz gravels are found passing under the limestone, and there has thus been shown on the accompanying map gravels both of Pliocene and Cretaceo-tertiary date. This showing of gravels of two ages seemed to be justified on account of the occurrence of quartz-gravels on the Quartz Ranges, which, underlying limestones there, are also in near contiguity to terraces that carry gravels of the younger date. Similar gravels lie at a lower level on the slope from the Quartz Ranges to the Aorere River. On the north-west side of the valley, what is probably an older series of gravels are developed on top of the hills opposite the junction of the Slate River. And, as shown by Mr. Park, other gravels of older date stretch from the Kaituna River along the north-west side of the Aorere Valley to the suspension bridge over the Aorere River above Rockville. These gravels are sometimes very coarse, and between Appo's Fat and the Pakihi Plain large boulders indicating glacier action are frequent, or, rather, abundantly met with. These gravels are believed to be auriferous, but there are no gold-workings at the present time in them. IV.—Miocene. These beds, as dark-coloured marly clays with septaria or cement concretions, are found mainly along the coast-line from south of Parapara Inlet to Collingwood. They contain fossils, but these have not yet been collected so as to determine what is the actual age of the beds. These same beds occur, forming hills, on the road from the Lower Kaituna to Rockville; but, according to Mr. Park, they are not known in the Upper Aorere Valley. The same beds should be represented on the north side of the valley. They overlie the limestone, and, as I am inclined to consider that as of Upper Eocene age, the clays overlying should be regarded as not older than Lower Eocene. V.—Eocene. This series of strata consists of shelly or indurated limestone, or calcareous greensands. The beds at places are full of fossils, and, from collections made at different times during past years, it would appear that these beds should be referred to the Mount Brown series of the Geological Survey classification, and consequently to the Upper Eocene period. Mr. Park, however, regards the limestones and underlying calcareous greensands as belonging to the Cretaceo-tertiary series, and, as belonging to this, distinguishes two limestones of similar character—one in connection with the Grey Marl series, and another belonging to the Ototara series ; but in the Aorere Valley it does not appear that this distinction can be maintained. Of the limestones and associated marly greensands, Park says : "In the Collingwood district they are chiefly confined to the north side of the Aorere, where they extend from the Kaituna, with occasional breaks, to a point half a mile above the junction of Clark's River. Their fossil contents tend to show that they are probably more nearly related to the Mount Brown series than to the Grey Marl series; but as it is difficult, even in the typical localities of the Waipara and Weka Pass, to define the boundaries between these two series, I have for stratigraphical reasons placed them in the lower."'* The evidence from fossils show that the beds belong to the Mount Brown series. Surely, then, the beds should have been referred to that series rather than to an underlying series to which the Mount Brown beds are supposed to be unconformable. It is true that in the Waipara and Weka Pass sections the evidences of stratigraphical unconformity between the Grey marls and the Mount Brown limestones may have been to Mr. Park somewhat obscure, and in the Weka Pass no doubt it is. In the Waipara section it is different. It should also be here stated that the Mount

• "Geological Reports," 1888-89, p. 241.