McKay. —Eastern and Central Otago.

3

Returning from Switzers to Dunedin , the Taieri Valley toMiddlemarch, at the foot of Strath-Taieri, was the field over whichthe last examinations for the purposes of this report were made.

During the latter part of February and the early part of March,1894, while accompanying Messrs. R. A. F. Murray, GovernmentGeologist of Victoria, and H. A. Gordon, Inspecting Engineer of theMines Department, on a trip over Central and Northern Otago,opportunity was afforded for further examinations that have beenuseful in making this report. Reports of previous surveys by variousworkers, and my acquaintance with a number of localities that on thisoccasion were not visited, enable me to deal with and describe thebeds at those places.

These examinations were chiefly made for the purpose of deter-mining the origin, mode of occurrence, and distribution of theauriferous quartz-drifts that are found throughout Central andEastern Otago and over a considerable part of the Southland District.At many places these beds are richly auriferous, and for a long timethere has been an uncertainty as to their identity in different parts,their mutual relationship, and their 2 iosition in the scale of geologicalformations. As the work progressed it became apparent that bedsvery similar to each other were not always of the same age, and thatin many cases the older auriferous drifts, on being denuded, hadyielded to the younger deposits a portion of their gold. There-fore, in order to show fully the importance of the more ancientdeposits, it is necessary to describe those which contain gold derivedfrom the older beds, and this involves generally a description of allthe beds of Cretaceous or Post-cretaceous age occurring within thedistrict examined.

Description of the Beds at Localities examined.

Gabriel’s Gully and Evans’s Flat .—Below the Township ofLawrence, Gabriel’s Gully gradually widens, until it opens out onthat part of the Tuapeka Valley called Evans’s Flat. The surfacealluviums of the river valley, which alone were worked in the earlydays of the rush, where they spread over a greater breadth, were lessrich in gold than above Lawrence, where the valley is much narrowed,and where, from side to side, the width of the alluvial deposit wasoften not more than from 2 to 3 chains. Above a certain point (theBlue Spur) the gravels of Gabriel’s Gully did not yield payable gold,and the lesser gullies, which below the Blue Spur are few and un-important, were also poor in gold. The workings along Gabriel’sGully showed distinctly that the source of the gold lay in the BlueSpur, and, in due course, the southern margin of the Blue Spurdeposit was prospected and proved gold-bearing.