Extent.

The boundaries in the Geological Map are, in many instances, only approximate, as I was unable for the greatest part to trace them myself. However, having had the advantage of obtaining a great deal of valuable information from Mr. Gerh. Mueller, the Chief Surveyor of Westland, and from several other friends in that province, upon whom I could rely, I believe that in a general way, the extent of this formation which promises to become, at no distant date, a large field for mining operations, will be found pretty correct. The Westland formation begins between the lower course of the Hokitika and Mikonui rivers, and stretches as far south as the Waikukupa, skirting the western foot of the Southern Alps. Small outliers occur between the latter river and the Mahitahi, after which it again attains large dimensions, page 257covering a great portion of the country between the Paringa and Waits rivers. From here to the northern banks of the Arawata river, it appears to exist only as isolated hills. I have coloured the slate formation on the south bank of the last-mentioned river as belonging to another formation, next to be considered. It consists of an alternation of silky clay slate and bluish felstones striking south-west and north-east, and having a dip of 70 to 80 degrees to the north-west. It is very possible that these beds may also belong to the Westland formation, the more so as I have since been informed that rocks belonging to the gneiss granite formation have been discovered south of the Arawata river.