ON SOUTH AFRICAN STRATA. 125 



and Dr. Walcofc Gibson; but it is rejected by three of the four 

 representatives of Cape Colony, while the fourth (Professor Schwarz) 

 would prefer the adoption of the name Barberton System. The term 

 Swaziland System is also rejected by Mr. Molyneux and Mr. Mennell, 

 the representatives of Ehodesia. The representatives of each State are 

 thus unanimous in their decision for or against the name Swaziland 

 System ; and as two States are for it and two against, there does nob 

 seem at present any chance of agreement. 



There is also no agreement on the Committee as to the name to be 

 adopted for the group to which these two systems probably belong. It 

 depends to some extent on the question of their age. 



The sedimentary series, including the quartzites and conglomerates 

 of the Band, were at one time believed to be Devonian; but they have 

 been gradually moved back to older and older horizons. At present 

 they are regarded as possibly Lower Palaeozoic (i.e., Silurian, Ordovi- 

 cian, or Cambrian), but more properly as pre-Cambrian. There is no 

 absolute evidence as to the age of either of the two great pre-Devonian 

 series. It will probably be generally admitted that the non-foliated 

 rocks are younger than the schists and gneisses. It is accordingly 

 tempting to compare the upper series of non-schistose sediments with 

 the Torridonian and Kew'eenawan, and the lower series to the crystal- 

 line schists which usually underlie the pre-Cambrian non-schistose 

 sediments. 



This view is, however, based only on lithological evidence. Some 

 members of the Committee are prepared to accept the view that there 

 is such a strong probability of widespread areas of such schists as those 

 of the Swaziland group being pre-Cambrian in age that, until definite 

 evidence to the contrary is forthcoming, they should be accepted as 

 Archean. Such a decision would be convenient, as it would enable 

 the rocks to be given a definite position in the colour scheme used on 

 the maps ; and, in the opinion of some members of the Committee, this 

 position is not likely to be altered. 



The terms available for these rocks are variously used, so it may be 

 convenient briefly to refer to their history and the present tendency as 

 to their use. 



If the Witwatersrand System and older schists be admitted as pre- 

 Cambrian, the first name for them to be considered is that of Archean. 

 This term was first proposed by J. D. Dana in 1872 in a paper on the 

 Green Mountain Quartzite. He there proposes to rule out the older 

 term Azoic, as the era in question was not throughout destitute of life. 

 ' I propose to use for the Azoic era and its rocks the general term 

 Archaean (or Archean), from the Greek apxettos pertaining to the 

 beginning. ' * In a footnote he objected to the term Eozoic, owing to the 

 doubtful nature of Eozoum, and explains, ' Whatever part of the 

 Archean beds are proved to belong to an era in which there was life will 

 be appropriately styled the Archeozoic. This term avoids the objection 

 which Eozoic derives from the doubtful nature of the Eozoum.' - 



Dana unquestionably proposed the term Archean to include the 



1 ' Green Mountain Geology. On the Quartzite.' Amcr. Jour. Sci., series iii., 

 vol. iii., 1872, p. 253- s Ibid. 



