ON SOUTH AFRICAN STRATA. 135 



but they appear to be divisible into two divisions which certainly recall 

 many of the features of the Animikies and Keweenawans of the Great 

 Lakes region in North America, and although, in default of evidence to 

 the contrary, it is probable that they are mostly pre-Cambrian, it is 

 possible that the Upper Vindhyans were formed since the days of 

 Olenellus. One cannot help being reminded by the Upper Vindhyan 

 red sandstones of the Cambrian purple sandstones of the Punjab Salt 

 Eange, and, because of the way they rest on old unfossiliferous rocks 

 of great thickness, of the Potsdam sandstones of America; but these 

 obvious temptations have to be resisted, for we have not only no fossil 

 evidence, in spite of apparently perfect conditions in the shales and 

 marls, but no definite periods of folding that could give a clue of cor- 

 respondence with the periods of marked folding in Europe. The term 

 Purana is thus of local value and cannot be offered except tem- 

 porarily to assist South African geologists. 



The term Algonkian, however, has still less claim to be used in South 

 Africa, and, after the mutilation it has undergone in America, it might 

 be dropped with advantage there also. The term Proterozoic implies 

 conditions that have yet to be established with certainty and is thus also 

 unsuitable. I would suggest, therefore, that a local term be used in 

 South Africa for the post-Archaean, pre-Palseozoic rocks. A term cor- 

 responding to Purana might be suggested by someone conversant with 

 the local languages ; otherwise a geographical term would have to serve. 

 The term Eparchaean should be confined to the great interval between 

 the Archaean and the oldest of the Witwatersrand System, for we should 

 not forget that the intervals of no record are as important almost in the 

 history of the world as the periods of sedimentation, and the interval 

 between the formation of the Swaziland schists and the Orange Grove 

 quartzites may have been as great in time as that which has transpired 

 since Olenellus lived. 



It would not assist the question to point out the lithological simi- 

 larities between the Witwatersrand, Ventersdorp, and Potchefstroom 

 (Transvaal) Systems and the Purana rocks of India; for if the Indian 

 term were used in South Africa it would be liable there, as here, to 

 decapitation on the discovery of fossils in the higher beds. One cannot 

 help noticing, however, the similar 'calico rocks,' the jaspers, and the 

 great trap-flows that are prominent in our older Puranas, and the 

 dolomitic, ' Olifantsklip ' limestones in parts of the higher beds. Not- 

 withstanding its obvious objections, I would rather use the term 

 Purana in South Africa than the term Proterozoic ; the establish- 

 ment of further correspondence with India is likely to be of greater 

 value to geology than would be the study of fancied resemblances 

 between South Africa and the Northern Hemisphere in Europe and 

 America. 



Transvaal Questions. 



6. I vote for the retention of the term Archaean. 



7. Swaziland Series seems unnecessary, unless it can be used for the 

 separation of the compact lithological series corresponding to the 

 Huronians (Lower Huronians) of America and Dharwars of India. 



