No. 483] NOTES AND LITERATURE 



193 



Mr. Campbell figures and briefly describes tlie mounds, reviews the 

 various theories of origin, some ten in number, uliich have been 

 advanced by various writers, and concludes from his own st\uiies 

 of the subject that the mounds have been built up by niits or small 

 rodents, more probably by ants. A bibliograpiiy \hv Mihjcri is 

 appended to the paper. 



Ancient Glacial Periods.— During recent years the evidences of 

 repeated glacial periods during ancient (^a-olopcal time have been 

 accumulating so rapidly that whereas much doubt \\ as cast upon the 

 earlier reports of such glaciation, it is no longer possible for the unpre- 

 judiced student to doubt the conclusions which the evidence forces 

 upon us. The famous Dwyka glacial formation of South Africa is 

 now well known, and its equivalent in India, the Talchir. I. C. 

 White and David White have recently rcn< h.d ihr conclusion, inde- 

 pendently, that the equivalent of these I'cnnian or Pen no-Carbon- 

 iferous glacial deposits occurs in south(M-n Brazil in w hat is called the 

 Orleans conglomerate dlarial deposits in Au-lialia arc reported 

 from both the I^'rniian and the Cambrian or older l.cl.. A. P. 

 Coleman has recently reported evi.lcn.c of a lower Ilnn-nian ice a-e 

 in Canada. Mr. Schwarz^ discusses three ulacial p. rio.l. in Sonth 

 Africa, those in addition to the Pennian Dwyka In ini: nu»t j.robalily, 

 according to the author, of Devonian and Archaean aire. The relation 

 of the glacial beds to other members of the ovneral ^tratiirraj^liic series 

 is pointed out, and the evidence of the glacial origin considered. It 

 is this last point which in every case is critical. The fart that a large 

 number of reports of ancient glaciation are being piiMi-hed does ,i,,t 

 strengthen the evidence in favor of ancient glaciation ni any ]iartienlar 

 case. Each reported instance must be critically exammed as to the 

 value of the evidence supporting it. 



