134 REPORTS ON THE STATE OP SCIENCE. 



the gneisses and schists, including many of obviously sedimentary 

 origin. Some of these, distinguished as the Dharwars in the south, and 

 as Aravallis, Champaners, and other local series in the north, recall many 

 of the features of the Lower Huronians of Canada and of the Swaziland 

 series in the Transvaal; hornblende-, chlorite-, and the talc-schists 

 interbedded with quartz-hematite and quartz-magnetite schists and, 

 rarely, crystalline limestones, are common types in these formations. 

 It is impossible to regard the closely folded Dharwars as having been 

 laid down on the exposed surfaces of the gneisses near by, when the 

 latter often show little more in the way of deformation than might be 

 regarded as flow structures developed during consolidation. Yet gneissic 

 pebbles are sometimes found in the Dharwar beds, though some of 

 these, at any rate, are doubtfully true conglomerates. 



Some of the gneissose granites, indistinguishable from typical 

 Archaean gneisses, are certainly younger than some Dharwars, and 

 generally it is impossible to unravel the mixture by any classification 

 dependent on age. It is, therefore, far more convenient to group all 

 such highly foliated rocks in peninsular India as Archaean. The name 

 involves no idea other than great age, and, has, therefore, none of the 

 objections that might be offered to such terms as Azoic, Eozoic, and 

 Archaeozoic. 



I do not see how the term Archaean can give rise to confusion in 

 South Africa, and it certainly does convey to the geologist the idea that 

 there exists a collection of very ancient rocks which have their nearest 

 probable equivalents among the Archaean of North America, India, and 

 other parts of the earth's surface where complications have not arisen by 

 post-Cambrian folding. There appears to be no call for the manufacture 

 of a local 1erm in South Africa or in India; our so-called Archaean rocks 

 may not be of the same age as those of America, but they have the 

 same relative position in the scale, the same characters, and, with the 

 perspective due to this distance of time, we are justified in regarding all 

 obviously Archaean rocks as equivalent. 



Algonlcian or Proterozoic. 



For the oldest rocks preserved after the great Eparchaean interval I 

 propose to use the term Purana in India. 1 The name means more 

 than merely old, for the Puranas, although very old in Indian literature, 

 are not the oldest; they are a rdchaufje of the more ancient Hindu 

 literature — the alluvial products derived from the basement complex of 

 the Archaaan Vedas. Before the term Purana was suggested we had 

 numerous local names for the old unfossiliferous formations resting on 

 the Archaean gneisses and schists — Cuddapahs, Bijawars, Gwaliors, 

 Pengangas, Chilpis, Kurnools, Kaladgis, Bhimas, and Vindhyans. We 

 have no positive evidence for the age of these rocks beyond the limits 

 Archaean below and about Middle Carboniferous above, the latter limit 

 being that determined by the base of the Talchir stage of the Gondwana 

 System. The Puranas may be wholly or in part pre-Cambrian in age, 



1 Holland : Presidential Address, Trans. Min. and Oeol. Institute of India, vol. i., 

 1906, p. 19< 



