500 



LOCAL SECTIONS 



A mile below the mouth of Miniskah River, another Trilobite bed, lower strati- 

 graphically than that of La Grange Mountain, is seen, just above the talus of rub- 

 bish and loose rock, at an elevation of one hundred and seventy-three feet above 

 the water. 



This Trilobite grit is slightly micaceous, and of a light greenish-gray colour ; its 

 thickness is about three feet, and the layers are thinly laminated. Besides several 

 species of Trilobites, it has yielded one small species of Orthis, and two species of 

 Lingulas. One layer contains those remarkable spines, belonging to a curious 

 species of Trilobite, in the shape of a fish-hook. The most common species is the 

 one we have hitherto designated as the Miniskah Trilobite. A third species also 

 occurs here, much smaller than either of the others, its cephalothorax scarcely ex- 

 ceeding two lines in length. 



Over the Trilobite grit are ninety-three feet of sandstone, the lower beds of which 

 are thinly laminated, and of green and yellow colours. The upper are thicker, and 

 have intercalations of magnesian limestone. On this reposes ten feet of ash- 

 coloured argillo-calcareous layers, containing DikelocepTialus Minnesotensis ; the 

 whole surmounted by soft brown and yellow sandstone, containing Lingulas. 



The Great Slide, about five miles below the mouth of the Miniskah, shows a 

 very instructive section of many of the members of F. 1. 







Feet. 



1. 



The talus at the foot of the bluff conceals the beds belonging to F. 1, c, 



66 



2. 



Green, and soft green sandstones, with scales of mica, 



25 



3. 



Brown calcareous rock, ....... 



4 



4. 



Layers of green sandstone, alternating with green earth, 



36 



5. 



Micaceous sandstone with Trilobites, . . . . . 



o 



6. 



Alternations of green and ferruginous sandstone, . . . . 



22 



7. 



Micaceous sandstones, with Dikelocrphalus Miniscaensw, 



3 



8. 



Loose green sand, and soft green sandstone, . . . . 



15 



9. 



Thin seam of greenish blue earth. 





10. 



Laminated green and yellow sandstone, . . . . . 



38 



11. 



Concretionary green, red, and yellow sandstone, with silicate of iron disse- 







minated, ........ 



3 



12. 



Green, red, and yellow compact sandstone, with thin dolomitic layers passing 







downwards into brown Orthis, and encrinital siliceo-calcareous rock, 



44 



13. 



Yellow and ash-coloured argillo-calcareous rock, containing Dikehccphalut 







Minnesotensis, and another species of Trilobite, 



9 



14. 



Alternations of thin-bedded and light brown and bluish sandstone, 



6 



15. 



Thick beds of soft yellowish sandstone, with hard, botryoidal concretions, 







passing downwards into light-coloured, fme-grained sandstone, 



51 



16. 



Mammillary and botryoidal layer of white sandstone banded with yellow, 



3 to 4 



17. 



Quartzose sandstone, with intercalations of magnesian limestone, with glisten- 







ing crystalline facets, ....... 



85 



18 



Lower Magnesian Limestone, ...... 



112 



525 



The next locality, " Mountain Island" {La Montague qui trempe a Veau) , exhibits 

 several of the lower beds of F. 1, in connexion with most of the preceding, and is 

 perhaps the best connected section of the stratification of F. 1 to be found on the 



