14 
THE GEOLOGY OF AUCKLAND. 
have been informed by Mr. Heapliy that these rocks are of 
wide-spread extent in the Middle Island, forming mountain 
ranges of great altitude, covered with perpetual snow, and 
reaching in Mount Cook probably to 13,000 feet. The rocks 
of these formations contain the principal metallic riches of the 
earth. Therefore we cannot hope to find these riches developed 
in the highest degree in the Northern Island ; but as other 
formations also contain metalliferous veins, there may be found 
many mines worth working in the rocks I am about to describe, 
I.-—PRIMARY FORMATION. 
The oldest rock I have met with in the Province of Auck¬ 
land belongs to the primary formation. It is of very variable 
character—sometimes being more argillaceous, of a dark blue 
colour (when decomposed, yellowish browm, the colour generally 
presented on the surface,) and more or less distinctly stratified 
like clay slate —(at Maraitai on the Waitemata) ; at other times 
the siliceous element preponderates, and, from the admixture of 
oxide of iron, the rock has a red, jasper-like appearance—(at 
Waiheki, Manganese Point.) In other localities it is more dis¬ 
tinctly arenaceous, resembling the Old Sandstones of the Silurian 
and Devonian Systems, called Grauwacke—(at Taupo, on the 
Haurald Gulf.) 
As no fossils have yet been found in this formation in New 
Zealand, it is impossible to state the exact age ; I am, however, 
of opinioiT that these argillaceous siliceous rocks will be found to 
correspond to the oldest Silurian strata of Europe. 
The existence and great extent of this formation are of con¬ 
siderable importance to this Province, as all the metalliferous 
veins hitherto discovered, or likely to be hereafter found, occur 
in rocks of this formation. 
To these rocks belong the Copper-pyrites , which has been 
worked for some years at the Kawau and Great Barrier —the 
Manganese (Psilomelan) at TVaihehi —and the Gold-bearing 
quartz at Coromandel , 
The gold which is washed out from beds of quartz-gravel in 
the rivers and creeks flowing down from both sides of Coro¬ 
mandel range, is derived from quai*tz veins, of crystalline char¬ 
acter and considerable thickness, running, in a general direction 
