Page:Quarterly Journal of the Geological Society of London, vol. 35.djvu/36

10 10 A. AY. HOWIIT ON THE PHYSICAL GEOGEAPHY AND

rated, and the planes of deposit can only be distinguished by alter- nating and undulating narrow lines of different colour. An exami- nation of the whole district shows, however, plainly that these in- clined and vertical strata dip downwards, becoming more and more altered, and generally end abruptly against the granite which occu- pies all the low ground and valleys.

Thus in the Deddick River a contour-line which would separate the high ground from the valleys would also approximately indicate the position of the granite as below this line. Were the whole of the granite stripped of the superior strata without being itself de- nuded, it would present an extremely uneven and irregular surface ; for we find, on examining the streams, that in places the Silurian strata descend below the general surface of the granite, and are much contorted and folded back on themselves, while in other places we find bosses of granite appearing through high ridges of the Silu- rian slates*.

The hard quartzites appear often to have marked out the ridges, as in Mount Bowen and Delegete Hill.

Among the much indurated and altered strata occasional patches are found which have been less affected, as, for instance, the black Graptolite-slates of Deddick, in close proximity to the granite boun- dary and the larger area of Bendoc and Delegete, where are situated mines both in auriferous alluvium and quartz veins. So far as I am aware, neither alluvial gold nor auriferous quartz veins have been met with at the Deddick Biver.

This Silurian formation extends beyond the coast-range down the Goungrah, Bern, and Cann rivers ; and gold- workings have been there opened. Little is as yet known concerning the geology or the resources of that part of tbe district ; it is mountainous and covered with dense scrubs, but it presents indications of being generally more or less gold-bearing. I have traversed it in three different directions, and can speak to the difficult nature of the country.

In respect to the other minor Silurian areas I need say but little. The general features are such as I have already noted. We find the same general direction of strike and high angle of dip, the same alternation of slates and sandstones with quartz veins, the same paucity of fossils, and the same intimate relation to the crystalline schists, the granites, and the older plutonic rocks generally, which I have yet to indicate more particular^.

This formation has been regarded as probably Lower Silurian. It has so far proved almost entirely barren of fossil remains through- out the district ; and it is only to the east of the Snowy Biver, as I have before said, that Graptolites have been met with f. These, the apparent connexion of the whole series, its relation to rock forma- tions of later age, the high angle of dip, amd the universally indu- rated and slaty condition of the strata as compared with others

tain at Bonang, and especially Mount Goungrah, as to the latter statements.
 * Accommodation Creek at Deddick as to the former, and Marriott's Moun-

t ' Prodromus of the Palaeontology of Victoria' &c, decade i. p. 12, by Fre- derick M'Coy, F.G.S., Government Palaeontologist, &c. &c.