CLIMATES OF GEOLOGIC TIME. 271 



"the Gaisa Beds, so far as I saw them, do not suggest the immediate neighbourhood of 

 a mountain-region, for such conglomerates as they contain are neither coarse nor plenti- 

 ful" (1897: 145). Again we have the evidence of tillites formed on low grounds and not in 

 the mountains. (For further detail see pp. 292-3.) 



UNDATED PROTEROZOIC GLACIATION. 



The following occurrences of tillites do not appear to be of latest Proterozoic time, 

 as do those of Australia and Norway. They are therefore held apart under a separate 

 heading from the tillites of earliest and latest Proterozoic time. 



North America. — Professor Coleman states that "Doctor Bell reports boulders reaching 

 diameters of 3 feet 8 inches, having grooves like glacial stria, in a conglomerate with 

 sandy matrix belonging to the Keweenawan of Pointe aux Mines, near the southeast end 

 of Lake Superior. Messrs. Lane and Seaman* describe a Lower Keweenawan conglomerate 

 as containing 'a wide variety of pebbles and large boulders, in structure at times suggestive 

 of till,' from the south shore of Lake Superior" (1908a: 354). 



India.— In peninsular India occurs the Kadapah system, which, according to Vreden- 

 burg, is made up of several series separated from one another by unconformities. The 

 Lower Kadapah is of Proterozoic age and the Upper Kadapah is certainly older than the 

 Siluric and probably even than the Cambric. In the Upper Kadapah occur "remarkable 

 conglomerates or rather boulder-beds consisting of pebbles of various sizes, some of them 

 very large, scattered through a fine-grained slaty or shaly matrix. * * * These peculiar 

 boulder-beds are regarded as glacial in origin" (1907: 20). 



In Simla occurs the Blaini formation, also with boulder-beds, the age of which, according 

 to Holland (see in David: 447) is certainly older than the Permic and possibly of late 

 Proterozoic time. It is "a conglomeratic slate composed of rounded pebbles of quartz, 

 ranging up to the size of a hen's egg, or in other cases angular and subangular fragments 

 of slate and quartzite, of all sizes up to some feet across, which are scattered at intervals 

 through a fine-grained matrix" (447). Holland regards these beds as "almost certainly of 

 glacial origin" (448). They may eventually be shown to be of late Proterozoic age. 



Africa.~In Proterozoic strata, far beneath the Table Mountain series of probably late 

 Siluric or early Devonic age, is the Griquatown or Pretoria series (29° S. lat.), in which 

 glacial materials have been found. At present no definite age in the Proterozoic era can be 

 assigned this formation, nor can it be said that the glacial horizon is either that of the Lower 

 Huronian or of the latest Proterozoic time. These are described by Schwarz as follows: 



"The Griquatown beds are a highly ferruginous series of shales and slates. * * * Near 

 the top of the series, in the district of Hay, west of Kimbcrly, there is a well-developed glacial 

 till, the matrix now converted into a red jasper; yet the bowlders of chert, when weathered out, 

 show the unmistakable facetting and scratching which can have been caused only by glacial 

 action. * * * The size of the bowlders varies up to 2 feet, and they are scattered at random 

 through the matrix, to which they bear a very small proportion in regard to bulk. * * * j 

 have found them in large numbers in some of the Witwatersrand conglomerates. The whole 

 thickness of the glacial till is probably under 100 feet, but the extent of country covered by it 

 in the area already mapped is over 1,000 square miles" (1906: 686). 



China. — In the provinces of the middle Yangtse River of China (110° E. long, and 

 31° N. lat.) Willis and Blackwelder (1907: 264-9; 1909: 39-40) found resting uncon- 

 formably upon very ancient granite and gneiss a series of quartzites followed by at least 

 120 feet of an unmistakable glacial tillite (in places nearly 500 feet thick), green in color, 

 which is in turn overlain by unfossiliferous limestones over 4,000 feet thick. This lime- 

 stone Wilhs correlates with the fossiliferous Middle Cambric occurring 100 miles away, 



* A. C. Lane and A. E. Seaman, Jour. Geol., 15, 1907: 688. 



