1867.] DAWSON — L.iUPvENTIAN EOSSILS. 257 



brown, having a thickness of sixty feet, and separated into beds by thin 

 layers of the mica-slates. The dolomite beds often pass into conglo- 

 merates, enclosing a multitude of well-rounded masses of gneiss, syenite, feet, 

 and quartzite, ranging in diameter from one to twelve inches 400 



5. Bluish and greyish mica-slates, studded in some places with crystals 

 of magnetic oxide of iron, and interstratified with an occasional band of 

 quartzite 500 



6. Grey and pinkish dolomite, weathering brown 100 



7. Grey micaceous limestone or calc-schist, interstratified with beds of 

 yellowish-brown sandstone, grey impiu-e limestone, white coarsely granular 

 limestone, and bands of dark -bluish compact limestone and black pyriti- 

 ferous slates. The calc-schist greatly predominates, and in Tudor it is cut 

 by several N.W. & S.E. lodes, containing galena in considerable quantity, 

 in a matrix of calc-spar and barytes. Near the middle of the mass, on the 

 surface of a three-inch band of the calc-schist in Tudor, on the fifteenth 

 lot of the Hastings road-range, east side, was obtained a fossil which 

 Dv. Dawson, after careful examination, pronounces to be Eozoon Cana- 

 dense 2000 



8. Green diorite-slates, interstratified with beds of fibrous diorite hold- 

 ing iron-pyrites, and with bands of mica-schist; somewhat below the 

 middle of the mass there occm's a six-feet band of white, highly crystal- 

 line limestone, in which is interstratified a bed of earthy graphite, with a 

 thickness of a foot ; and a three-feet bed of finely granular white iron- 

 pyrites imderlies the limestone. These diorite-slates graduate downwards 

 into mica-slates, which are interstratified with frequent bands resembling- 

 serpentine, and some of green and reddish coarse soapstone, which has 

 been used for furnace-hearths. These mica-slates graduate into green 

 massive hornblende-rock or amphibolite, the weathered surface of which 

 in some places shows subradiating forms of hornblende. The amphibo- 

 lite finally passes into diorite-slates, composed of the same green horn- 

 blende, with a large admixture of albite. These four groups of rock occupy 

 a breadth of 15,000 feet, standing in a vertical attitude on the east side of 

 Elzivir ; and as there is reason to suppose that they fold over sharply on 

 themselves, their volume is estimated at 7500 



9. Eeddish granitic gneiss, the total thickness of which has not been 

 ascertained, but is for the present estimated at 2100 



20,000 



2. Notes on Fossils recently obtained from the Laueentian Eocks of 

 Canada, and on objections to the Oeganic natfee of Eozoon. 

 By J. W. Dawson, LL.D., P.E.S., F.G.S. With Notes hy 

 W. B. Caepentee, M.D., F.E.S. 



[Plates XI. & XII.] 



Contents. 



Specimen of Eozoon from Tudor, 

 C. W. 



1. General Appearance. 



2. Microscopic Characters. 



3. Concluding Eemarks. 



II. Specimens from Long Lake and 

 Went worth. 



III. Specimens from Madoc. 



IV. Objections to the Organic na- 



ture of Eozoon. 



I. Specimen op Eozoon eeom Tudoe, C. W. 

 This very interesting specimen, snbmitted to me for examination by 

 Sir W. E. Logan, is, in my opinion, of great importance, as fur- 

 nishing a conclusive answer to all those objections to the organic 

 nature of Eozoon which have been founded on comparisons of its 

 structures with the forms of fibrous, dendritic, or concretionary 



