165 
until covered by tbe Tertiaries, tbe rocks in situ appear to be either 
Silurian or Upper Ordovician, more likely tbe latter. They consist 
of coarse, gritty sandstones, quartzites, and finer sandstones, with a 
considerable amount of mica, and iron pyrites in small veins. Other 
bands of greenish slates are acutely folded, and pitch steeply, in one 
instance, below the bridge, at an angle of 70° west. The last of 
the series appears about 9 chains above the bridge as slate, much 
crushed and folded. 
ISTorthwards along the Tara Range there are, in places, outcrops of 
Upper Ordovician rocks; these are well developed along the tourists’ 
track to Buchan, and about 5 miles from Uowa Uowa a cutting has 
been made—Harris’ cutting—where dark-blue mudstones were cut con¬ 
taining Upper Ordovician graptolites. A collection from these beds 
was previously made by Mr. O. A. L. Whitelaw, and determined by 
Dr. T. S. Hall.^ Upper Ordovician rocks extend eastwards for over a 
mile from the cutting, and in a gully half-a-mile east graptolites were 
collected from crushed and broken slates, which sometimes assume the 
form of pale and black, much-shattered cherts. Bouth-easterly from 
Buchan there are some prominent, rather sharp, peaks, composed in 
part of pale-blue to white slates and sandstones. Urom a spur which 
tends westwards from this portion of the range I obtained from decom¬ 
posed slates graptolites apparently of Upper Ordovician age. From 
South Buchan the range tends north-east to the junction of Back Creek 
with the Snowy River; north of this junction Upper Ordovician 
graptolites were collected from pebbles of black slate in Butcher’s Creek, 
Murrendal, and still further north in slates and cherty slates on the 
slopes of Mt. Deddick. 
The rocks at Ironstone Creek, about 1 mile north-east of the ISTowa 
ISTowa Hotel, consist of slates, sandstones, and quartzites folded and 
much criLshed, and striking about H. 30° E. They are Upper 
Ordovician or possibly Silurian, and are apparently portion of the 
Boggy Creek series. The beds below the bridge over Ironstone Creek 
are an extension of the supposed Ordovician sediments, and above it 
are bedded tufis, &:c., of which I made no personal observation. 
A small exposure of peculiar, possibly Ordovician rocks, occurs at 
Monday and Stony Creeks, respectively 4 and 4 :^ miles from ISTowa 
ISTowa, on the Bruthen-road. They are almost horizontally bedded, and 
are highly metamorphosed, being micaceous and feebly crystalline. 
There are some members of the felsite series in the vicinity, either 
dykes or bands of porphyry. 
It would appear that a belt of Upper Ordovician rocks occurs at 
the surface, as inliers, surrounded by the Snowy River porphyries, or 
Middle Devonian limestones. Various observers have referred to the 
fact that throughout Gippsland portions of the great porphyry series 
have been intruded through the Ordovician series. 
Snowy River Fragmental Quartz Porphyry Series. 
Hine chains above the ISTowa Howa bridge, along Boggy Creek, rocks, 
which probably belong to the Snowy River quartz-porphyry series. 
^ T. S. Hall, Reports on Graptolites, Rec. Geol. Surv. Viet., Vol. III., Pt. 2, p. 209. 
