l60 



GEOLOGY. 



correlation of the Yictorian auriferous drifts, deep-leads, and fossili- 

 ferous Tertiary rocks, and on the past and present flora follow. Ee- 

 marks on the gold-fields and mineral districts comj)lete this part. 



Ten special Reports follow: — 1. A. W. Hewitt. Notes on the 

 Geology of Part of the Mitchell River Division of the Gippsland Mining 

 District, pp. 59-73. Describes deposits of the following periods : — 

 Recent. — U. Tertiary, or Moitun Creek group, consisting of sandy and 

 clayey marine beds 400 to 500 ft. thick. Those overlie the older for- 

 mations, and fill a deeply excavated area at the contact of the Bairnsdale 

 limestones and Avon sandstones. — Middle Tertiary, or Bairnsdale Lime- 

 stone Group. Varies from a yellow friable calcareous rock to a hard 

 yellow limestone with marine fossils ; covers a large area from W. of 

 the Mitchell R. to the E. side of Lake Tyers. — Avon liiver Sandstone 

 Group (Carboniferous). These beds, which consist of a thick series of 

 sandstones, grits, conglomerates, and thin shales, once formed an anti- 

 clinal arch over N.E. Gippsland, but have suff'ered greatly from denu- 

 dation. Two groups are recognizable, the lower with plant remains, 

 which McCoy thinks may be U. Devonian. The Avon sandstones at 

 Mt. Alfred, &c. rest upon trappean rocks of varying lithological cha- 

 racters ; they are younger than the L. Silurian but older than the 

 Avon River group. — L. Silurian. A series of unfossiliferous slates 

 and felspathic and micaceous sandstone, dipping at a high angle, form 

 the oldest rocks. Concludes with remarks on the gold-workings. 



2. A. W. Hewitt. Notes on the Geology of the Ovens District, 

 with Remarks on the Deep Leads, pp. 74-82, plate 1 (sketch section 

 from Wahgunyah to Mt. Stanley). The formations of the S.E. part of 

 the district are Silurian and granite, forming a hilly and mountainous 

 country, in which are the gold- workings of Beechworth, Yackandandah, 

 &c. The S.W. part consists of the "Murray Tertiaries," forming 

 generally a low and level country. The Silurian strata of Beechworth 

 have been generally affected by slaty cleavage, and the granites have 

 been intruded after the tilting and folding of the Silurian rocks and 

 the formation of the auriferous quartz-veins. At Tarrawingee, near 

 Beechworth, are a series of thick sandstones and grits, which may be 

 U. Pala)ozoic or Mesozoic. The deep-leads of Wahgunyah, &c. re- 

 present the former extensions of the present streams, and are from 300 

 to 400 ft. below the present surface. Considers that since the deep- 

 lead epoch a subsidence of about 1000 ft. has taken place, followed by 

 a re-elevation, but not so great. The alluvial gold of the Beechworth 

 district has been derived from the Silurian rocks and not from granite. 



3. N. Tayler. Report on the Geological Survey of the Stawell 

 (Pleasant Ck.) Goldfield, pp. 84-92, plate 2 (Section of Commercial 

 Street Lead, Stawell). The Granite around Stawell consists of a 

 tertiary compound of probably two varieties of felspar, quartz and 

 black mica. The metamorphic rocks near the granite-boundary are 

 much altered. The elvan dykes are usually met with in sinking on 

 the reefs and in the " leads," are generally hard, but where overlain by 

 drifts are decomposed into a soft kaolin, and are believed to be older 

 than the quartz-reefs. The Quccrtz-Reefs are now worked at a depth 



