56 



of the Agnes Eivulet, I have little hesitatioa in pronouncing 

 it to be of earlier date than any which has hitherto been 

 recognised in the above-mentioned area. It varies in character 

 from a soft arenaceous clay slate to a hard compact grit, con- 

 taining in places rolled pebbles and boulders of schistose or 

 metamorphic rocks, with porphyries and granite, and is in all 

 respects analogous to portions of the old conglomerates of the 

 North Coast, which are undoubtedly of Silurian age. It occurs 

 on both sides of the Agnes Eivulet, which seems to occupy a 

 synclinal hollow, and it is evidently unconformable to the 

 IJpper Palaeozoic mudstones by whose denudation it has been 

 exposed. The ruling angle of dip is about 60°, the strike 

 being nearly north and south. The rock is in places highly 

 impregnated with iron pyrites, and I noticed faint impressions, 

 apparently of organic origin, but too indistinct to be made 

 out on the spot, and the matrix too perishable to allow of its 

 removal for examination. Until some fossils have been dis- 

 covered and identified, all further speculations as to geological 

 age are quite futile, but the search for them I must leave to 

 those who have plenty of leisure time. 



The existence in this neighbourhood of an interesting porphy- 

 ritic rock, containing large crystals of felspar, has long been 

 known. Though peculiar to the district it is analogous in 

 several respects to many common members of the trappean 

 series, but the entire absence of hornblende, which in them is 

 a distinguishing feature, is noticeable. It is clearly newer 

 than the grit just described, which it intersects in the form of 

 a vast dyke on the western side of the township, another 

 branch showing itself in a quarry near the new slab road ; 

 and it seems probable that the quartzose veinstones, which 

 have been quite recently met with, and which appear to 

 traverse the porphyry near some of its points of contact with 

 the older rocks, are the source of the gold which has been 

 sparingly found in the alluvium of adjacent gullies. Whether 

 a careful assay of specimens from these veinstones will result 

 in the establishment of this theory remains yet to be proved. 

 Unfortunately the most interesting part of the quarry last 

 referred to, is now under water, and there is no other spot in 

 the neighbourhood which affords similar facilities for investi- 

 gating the subject. There are well authenticated instances 

 in Victoria of the occurrence of auriferous veins of similar 

 character in diorites closely allied by their geological relations 

 to the porphyry of Port Cygnet, but I see no grounds at pre- 

 sent for advising any large outlay in the search for gold. It 

 is clear that in the shallow alluvium, where it has hitherto 

 been found, there is no prospect of an adequate return for the 

 expenditure of labour and capital, and it is equally clear that 



