58 THE DAWN OF LIFE. 



limestone, occasionally interstratified with diorites, and 

 near the base with silicious slates and small beds of 



impure steatite 330 



This limestone, which is often silicious and ferrugin- 

 ous, is metalliferous, holding disseminated copper 

 pyrites, blende, mispickel, and iron- pyrites, the latter 

 also sometimes in beds of two or three feet. Gold occurs 

 in the limestone- at the village of Madoc, associated with 

 an argentiferous gray copper ore, and in irregular veins 

 with bitter-spar, quartz, and a carbonaceous matter, at 

 the Richardson mine in Madoc. 



6. Gray silicious or fmed-grained 'mica-slates, with 

 an interstratified mass of about sixty feet of yellowish- 

 white dolomite- divided into beds by thin layers of the 

 mica-slate, which, as well as the dolomite, often becomes 

 conglomerate, including rounded masses of gneiss and 

 quartzite from one to twelve inches in diameter 400 



7. Bluish and grayish micaceous slate, interstratified 

 with layers of gneiss, and occasionally holding crystals 

 of magnetite. The whole division weathers to a rusty- 

 brown 500 



8. Gneissoid micaceous quartzites, banded gray and 

 white, with a few instratified beds of silicious lime- 

 stone, and, like the last division, weathering rusty 

 brown 1,900 



9. Gray micaceous limestone, sometimes plumbagin- 

 ous, becoming on its upper portion a calc-schist, but 

 more massive towards the base, where it is interstratified 

 with occasional layers of diorite, and layers of a rusty- 

 weathering gneiss like 8 1 ,1 00 



This division in Tudor is traversed by numerous 

 N.W. and S.E. veins, holding galena in a gangue of 

 calcite and barytine. The Eozoon from Tudor here 

 described was obtained from about the middle of this 

 calcareous division, which appears to form, the summit 



of the Hastings series. 



Total thickness .. .. 21,130 



