Extent.

In the northern portion of the Province it covers a great deal of ground, where it forms Mount Brown, the Deans, Mount McDonald, and a number of well defined peaks as far as Mount Vulcan on the southern banks of the Motenau river, near the sea coast. Some of the calcareous greensands, forming small hills in the Hurunui plains, may also belong to this formation. South of Mount Brown, the Oamaru beds partly surround Mount Grey, where the so-called White Rock quarry is situated amongst them. They continue to the northern banks of the Ashley river, where their traces are lost. We meet them again at the so-called Curiosity Shop, a small outlier surrounded by post-pliocene alluvium and morainic deposits, on the left bank of the page 305Rakaia, six miles below the gorge, and well known to the settlers o£ this Province for years past as a favourable locality for collecting fossils. We find also south of the Rakaia, strata belonging to the same system, where the Taylor branch of the Ashburton enters the plains, and meet with them still more largely developed on both banks of the southern Ashburton, as well as near the sources of the northern Hinds. They also fringe the Canterbury plains from the Orari to the Kakahu, after which they cover a considerable extent of country, from the middle course of the Opihi north to the Otaio south. Another large zone extends along the middle course of the Waihao branches, and along both banks of the lower Waitaki. During the deposition of this formation, the land sank so considerably that we find now within the alpine ranges beds belonging to it, as high as 5000 feet above the present sea-level. Moreover, it is evident that at one time, wherever favourable chances prevailed, deposits belonging to that formation must have been formed all along the eastern slopes of our Alps, because in many spots small outliers (which have escaped the general destruction) belonging to this formation, have been preserved. Of these localities, those of the Esk, in the Broken River basin west of Mount Torlesse, on both sides of Lake Heron, in the River Potts (east of Mount Potts), between the upper Opuha and Opihi, and near the sources of the Hakataramea, are the most important ones. The Oamaru formation seems to be entirely absent from Westland.