1868.] LOGAN — NEW SPECIMENS OF EOZOON. 31 t 



)!. Crystalline limestone, sometimes magnesian, including lenti- 

 cular patches of quartz, and broken and contorted layers of 

 quartzo-felspathio rock, rarely above a few inches in thickness. 

 This limestone, which includes in Elzivir a one-foot bed of 

 graphite, is sometimes very thin, but in other places attains a 

 thickness of 750 feet ; estimated as averaging 400 



4. Hornblendic and dioritic rocks, massive or schistose, occasion- 

 ally associated near the base with dark micaceous schists, and also 

 with chloritic and epidotic rocks, including beds of magnetite; 

 average thickness 4,200 



5. Crystalline and somewhat granular magnesian limestone, 

 occasionally interstratified with diorites, and near the base with 

 silicious slates and small beds of impure steatite 330 



This limestone, which is often siliceous and ferruginous, is 

 metalliferous, holding disseminated copper pyrites, blende, mis- 

 pickel, and iron pyrites, the latter also sometimes in beds of two 

 or three feet. Gold occur in the limestone at the village of 

 Madoc, associated with an argentiferous grey copper ore, and in 

 irregular veins with bitter-spar, quartz, and a carbonaceous 

 matter at the Richardson mine in Madoc. 



6. Grey silicious or fine-grained mica-slates, with an interstra- 

 tified mass of about sixty feet of yello wish- white dolomite divided 

 into beds by thiu layers of the mica-slate, which, as well as the 

 dolomite, often becomes conglomerate, meludiug rounded masses 



of gneiss and quartzite from one to twelve inches in diameter. . . . 400 



7. Bluish and greyish 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 grey and white, with 

 a few instratified beds of silicious limestone, and, like the last 

 division, weathering rusty brown 1,900 



9. Grey micaceous limestone, sometimes plumbaginous, becom- 

 ing 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 1,000 



This division in Tudor is traversed by numerous X W. and S.E. 

 veins, holding galena in a gangue of calcite and barytine. The 

 Eozoon from Tudor here described was obtaiued from about the 

 middle of this calcareous division, which appears to form the 



summit of the Hastings series. 



* Total thickness 21,130 



*In explanation of the apparent discrepancies between the above 

 section and the one given in the Quarterly Journal of the Geological 

 Society, it is to be said that 8 and 9 of the latter section are repetitious 

 of 1 and 2 on the other side of a synclinal, and that 2 in that section 

 represents but a small exposed portion of the great mass of 8, whose 

 measured thickness, as there stated, is 15,000 feet, and includes divisions 

 2, 3, and 4 of the present section. — Eds. 



