90 



acres, now traversed by the National Transcontinental Rail- 

 way, and known as the " great clay belt," in which exposures 

 of solid rock are few in number. The clay on both sides of 

 the height of land is pretty uniform in character. 



Following is an analysis of the clay in a cut on the 

 railway between Haileybury and New Liskeard. It will 

 be seen that the lime and magnesia are rather high. This 

 is owing to alternate bands containing considerable marl. 

 The clay effervesces strongly in acid. 



Per cent. 



Silica 52.00 



Alumina 16.11 



Ferric oxide 4.69 



Lime 8.26 



Magnesia 4.10 



Potash 1.74 



Soda 2.76 



Sulphur trioxide .09 



Loss on ignition 9.64 



Total 99-39 



THE COBALT-SILVER VEINS. 



The cobalt-silver veins occupy narrow, practically 

 vertical fissures or joint-like cracks in rocks of three ages, 

 viz. : Cobalt series, Keewaitin series and Nipissing diabase. 

 The relations of the veins to each of these three groups of 

 rocks are shown in the accompanying generalized cross- 

 section of the Cobalt area and in the larger scale, colored 

 cross-section, (plate IV), published by the Ontario Bureau 

 of Mines. The veins are much more numerous in the rocks 

 of the Cobalt series than in the Keewatin or Nipissing 

 diabase. 



It was estimated that up to July 1st, 191 1, the yield from 

 the Nipissing diabase had been approximately 7.55 million 

 ounces from 12 veins, or 629,000 per vein, or 7 per cent, of 

 the total production. The Keewatin with 13 veins had pro- 

 duced 1 1.7 million ounces, or nearly 1 million per vein, or 

 10.85 P er cent, of the total. From 86 veins in the Cobalt 

 series there had been obtained 88.55 million ounces, or a 



