388 INDEX TO THE STRATIGEAPHY OF NOETH AMERICA. 



M 11. FRONT RANGE, ROCKY MOUNTAINS OF ALBERTA. 



The Banff series, consisting of upper shale, upper Hmestone, lower shale, and 

 lower limestone, in the order named, constitutes the Carboniferous and possibly 

 Upper Devonian of the eastern range of the Rockies in Alberta. McConnell ^^^^ 

 describes the strata as follows : 



The Cretaceous is underlain by the Banff limestone, of Lower Carboniferous or Upper 

 Devonian age, and, notwithstanding the complete absence of all the intervening formations, 

 no unconformity was anywhere detected between them, except where faulting is known to 

 have occurred. The apparent conformity is perfect, even in the clearest sections, and the 

 difficulty in drawing an exact line between the two series is further increased by the close litho- 

 logical resemblance which the upper part of the Banff limestone bears to the lower beds of the 

 Cretaceous. 



The Banff limestone series has a total thickness of about 5,100 feet and is divisible into a 

 lower and upper limestone and into lower and upper shales. 



The upper shales vary in tMckness from 500 to 1,500 feet but are usually in the neighbor- 

 hood of 700 feet, and where this is much exceeded, as at the mouth of Johnson Creek, there is 

 reason to suspect that some of the Cretaceous beds are included with them. They exhibit great 

 diversity in structure and pass, according to the amount of arenaceous matter present, from 

 finely fissile shales through flaggy and ordinary sandstone into hard quartzite. The quartzites, 

 where present, occupy the lower part of the division and are overlain by the shales, and the 

 two sets of beds in this position can occasionally be traced from one end of the range to the other. 

 In other cases, however, this regularity is wanting and shales constantly pass into quartzites 

 and vice versa. These shales are often calcareous or dolomitic and in places are represented 

 by an impure limestone, and they always contain sufficient iron to give them a reddish color 

 when weathered. They are found on the western slopes of most of the ranges in the eastern 

 part of the chain and also in the bottoms of most of the longitudinal valleys of the same district, 

 as from their relative softness they are one of the vaUey-making formations of this part of the 

 range, an office which they fill in common with the Cretaceous shales. The Upper Banff shales 

 are underlain by about 3,000 feet of limestone, which may be called the Upper Banff limestone 

 in order to distinguish it from the lower limestones of the same series. This usually occurs as a 

 grayish, purely calcareous and welVcrystallized rock but is also found under a number of other 

 forms. It is often dolomitic, and hard, bluish, compact beds are not uncommon, nor are shales 

 and sandstones altogether absent. Its most characteristic features, however, are the abundance 

 of crinoidal remains which it everywhere shows (some of the beds being wholly composed of 

 the broken stems of crinoids) and the cherty concretions which are distributed through it, either 

 irregularly or arranged in lines along the bedding. These concretions are especially abundant 

 in Pilot Mountain and along the western side of the Sawback Range and in both these places 

 are often united into thin irregular beds. They also become more numerous toward the top of 

 the limestone and are occasionally continued on into the shales. 



Below these limestones come from 500 to 700 feet of shales and shaly limestone, constituting 

 the Lower Banff shales. The shales are dark colored but usually weather red and are somewhat 

 arenaceous and pass into flaggy sandstone. They are also nearly always calcareous, and in 

 places the series is represented altogether by impure shaly limestones. At a point about 2 miles 

 up a smaU creek, which joins the Bow River gap, this group is underlain by from 15 to 20 feet 

 of coal-black fissile shales, which rest directly on the massive limestone beds of the underlying 

 formation and are interesting on account of their f ossiliferous character. A number of specimens 

 of a Clymenia, besides other fossils, were collected here. At one point these black shales bend 

 around a large and well-rounded limestone bowlder, belonging apparently to the Castle Mountain 

 group, and looking exactly like an erratic of the glacial drift. 



The lowest division of the Banff limestone consists of from 600 to 800 feet of heavily bedded 

 bluish and fairly compact limestone. In composition it is mostly calcareous, but it also contains 

 a certain amount of dolomitic matter distributed in an irregular manner through the beds and 



