PROCEEDINGS OP SECTION C. 469 



land nortli of the tigli ranges which fringe the shore is practically un- 

 known. Mr. Moore marked out a track through to D'Entrecasteaux 

 Channel, but I do not know that anyone besides himself has ever gone 

 through on it. 



A recent visit to the bight has enabled me to construct the follow- 

 ing table of the geological succession there : — 



Recent. — Swamp and lagoon land at foot of terrace ground. This 

 deposit descends to a few feet below sea-level. 



Terraces of tin-bearing detritus and wash at the foot of the coastal 

 mountains, from 50ft. to 150ft. above sea-level. 



Tertiary. — Terrace of clayey sand, with carbonaceous material 

 fringing foot of mountains, 150ft. to 200ft. above sea-level. 



Jura-Trias and Pertno-Carboniferous. — Not represented. 



Devonian (?). — Biotite-granite forming the bed rock below the 

 terraces and exposed from sea-level up to 600ft. Intrusive in 

 quartzite and schist and intersected by veins carrying tin ore, with 

 accessory molybdenite. 



Hornblende-lamprophyre intrusive in quartzite. Found as loose 

 stones on beach at east end of the western bay. 



Veins of griesenised quartz intrusive in quartzite near the junction 

 of latter with granite. 



ActinoHte contact rock as loose stones on beach near Sand Bluff. 



Silurian, Ordovician, and Cambrian.— Not identified. 



Pre-Cambrian (?) Algonkian. —QueLvtzite of Cox's Bluff Range, 

 Foley's Pimple, Bathurst Range, Red Point Range. 



Mica Schist and quartzite at Point Eric. 



Mica Schist at Black Point. 



Slate and sandstone on Slate Range. 



Silvery mica schist on fall of range to Louisa Bay. 



The bight is six miles across, and is divided into two bays by a 

 small promontory called Point Eric, which rises to a peak 160ft. above 

 sea-level. This headland is composed of alternate beds of biotite 

 schist and saccharoidal quartzite, greatly contorted and dipping at 

 low angles to the south-west. The strike of these strata is north-west 

 and north-north-west. These are the general strike and dip of all 

 the schists and quartzites in the locality, excepting in the case of a 

 range of dark muscovite schists on the eastern bay, where the strike 

 is only a few degrees west of north. At the neck of the Point Eric 

 promontory a junction with granite takes place, and the latter forms 

 a spur with rocky knobs rising north from sea-level to 600ft., where it 

 again junctions with quartzite, which continues to the summit of the 

 Bathurst Range, 2,800ft. above sea-level. Cox's Blufi Range is a high 

 headland (about 1,000ft.) forming the western horn of the bight, and 

 consisting of quartzite, like many of the bluffs which jut out on this 

 part of the south coast, with bare snow-white crests visible for many 

 miles. The dense white quartzite of Port Davey has long been con- 

 sidered to be of Pre-Cambrian age, not to say Archaean. 



These mica schists are intimately involved with the undoubtedly 

 sedimentary quartzites : this and the absence of gneisses and eruptive 



