Geological Society, 443 



assigning a portion of it, (as in the vicinity of Lake Winipeg,) to the 

 mountain-limestone of Europe, he justly remarks that in other places 

 the quantity of gypsum, in connection with copious salt springs, and 

 great abundance of petroleum, together with the occurrence of soft 

 marly-sandstone, and beds of breccia interstratified with those of 

 dolomite, and above all, the fact that dolomitic limestone is by far 

 the most common and extensive rock in the deposit, would lead to its 

 identification with the zechstein of continental geologists, — the mag- 

 nesian limestone of the North of England. 



5. Above the limestones, and in some cases, it would appear, 

 alternating with the dolomite, is a very extensive deposition of sand- 

 stone, bituminous-shale, and slaty- clay (which last exhibits in some 

 places the peculiar structure denominated cone-in -cone) containing 

 nodular ranges of clay-iron-stone and beds of lignite. The shales 

 include impressions of ferns, lepidodendrons, and other vegetable 

 remains $ and among the fossils of this formation was also found an 

 ammonite, supposed by Mr. Sowerby to belong to a part of the 

 oolitic series of England. It deserves inquiry therefore, whether 

 this may not be the equivalent of the carboniferous strata which form 

 a portion of the oolitic series in Yorkshire, and at Brora in Scotland. 



The series of beds above described occurs extensively in the 

 course of the Mackenzie River, and on the shores of the Great Bear 

 Lake j and from its being found also on the northern coast, at a 

 distance of about 300 miles from thence, and in a direction precisely 

 corresponding, it not improbably occupies the intervening country. 



About Cape Bathurst (lat. 70° 36', long. 127° 35') cliffs of alum 

 shale form the coast for more than 60 geographical miles, and are 

 described as resembling those of Whitby in Yorkshire. 



6. On the promontory of Cape Lyon are extensive ridges of co- 

 lumnar trap associated with limestone and slate-clay j and green- 

 stone is of frequent occurrence there and in some other places. 

 Porphyry also, forms low conical hills in the high ground between 

 the Copper Mountains and Bear Lake. 



7. Near the western boundary of the limestone, and not far from 

 the base of the Rocky Mountains, there occur at intervals, from lat. 

 50° to 69° N. extensive [tertiary?) deposits, consisting generally of 

 sandstone, gravel, clay more or less bituminous, and brown wood- 

 coal. In some spots the wood-coal was replaced by an excellent 

 pitch-coal, the fractured surface of which is marked with very peculiar 

 concentric semicircular depressions j and it is interesting to know 

 that this coal, which would be excellent fuel for a steam-vessel, occurs 

 on the coast of the Polar sea near the Mackenzie in considerable 

 quantity. This formation contains layers of a variety of pipe-clay which 

 is eaten by the natives, and is said to sustain life for a considerable 

 time. The deposit at the mouth of Bear Lake River includes some 

 beds of impure porcelain earth. The author found occasionally much 

 difficulty in distinguishing the sandstones and shales of this deposit, 

 from those of the formation mentioned above in Section 5. 



8. Among the indications of other strata more recent than the 

 magnesian limestone, was a loose fragment of soft limestone found 



3L2 at 



