BY THE RET. J. E. TENISON-WOODS, F.G.S. 375 



beds. Eut veins of tin have also been found in Herberton 

 (Queensland) as rich as any in the world. 



Earlier Paleozoic Rocks. — In connection with the Grranites, 

 the Slates and Schists of the Cambrian, and probably Laurentian 

 periods, are found. In these are the veins containing gold and 

 other metals. As a rule, the veins consist more of Felspar than 

 any other mineral, and their direction is more often meridional 

 than otherwise. It appears that the auriferous veins in the 

 Cambrian formation of the colony of Victoria are much more 

 nearly north and south than those of the Silurian.* 



The gold veins in Cambrian E-ocks in the same colony are 

 probably eight times more numerous than the Silurian. Asa 

 rule the greater number of veins run parallel with the strata in 

 which they are enclosed, and the greater number of the richest 

 veins strike west of north. In California and Brazil veins run 

 parallel to the mountain chains. In Australia they do so on the 

 eastern side of the Continent, but where the edge of the table 

 land bends round to the north-west the veins still keep their 

 north and south direction. They are therefore independent of 

 the present configuration of the land. East and west veins are 

 usually poorer than the meridional ones, which is not the experi- 

 ence of other countries. It would appear also that, as a rule, 

 gold is not embedded in the quartz, but occurs in a comparatively 

 loose state in the midst of cavities and laminations. 



* The terms used in the Geological Survey of Victoria are those of Murchison 

 and his divisions of upper and lower Silurian are followed in that colony. 

 But this system and nomenclature are not generally adopted, from the in- 

 justice it does to Sedgwick's prior investigations. Following the example 

 of many Geologists, I restrict the term Silurian to Murchison' s Upper Silurian 

 (Ludlowiks, Wenlock, May Hill, or Upper Llandovery). The Buala or 

 Caradoo are Siluro-Cambiian, and all the rest of Murchison's Lower Silurian 

 are Cambrian, But instead of using the term Siluro-Cambrian 1 should 

 much prefer that proposed by Prof. Lupworth (Geol. Mag.forJ879) Ordovecian 

 which has much to recommend it. 



