274 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



Feet Meters 



le. Massive-bedded, gray limestone breaking up into thinner 



layers and ^ inch to 8 inches (1.3 to 20.3 cm.) thick, 



with a few layers 4 to 8 feet (1.2 to 2.4 m.) thick and 



with many large (8 to 12 inches, 20.3 to 30.5 cm.) 



concretionary forms. At 75 to 90 feet (22.9 to 27.4 m.) 



from bottom the Kainella fauna occurs in soft gray 



limestone layers (67t) ; 17b 51.8 



Total of Mons 783 238.6 



UPPER CAMBRIAN 

 Lyell Formation 



10. Thick-bedded, coarse, gray dolomitic limestone forming 

 high cliffs overlooking the headwaters of Panther 

 River (see pi. 36). 

 Section broken by fault line. 



Castle Mountain Section 



The bold, castellated southwest front of Castle Mountain overlooks 

 the Bow River Valley, its higher towers appearing like the ruins of a 

 great castle rising to an elevation of 9,976 feet (3,040.7 m.) or 4,000 

 feet (1,219.2 m.) above the Bow River. There is a large amphitheater 

 near its southeastern end that has a high ridge on its northeastern side 

 (Helena Ridge, 9,390 feet [2,862.1 m.]) and an elevated point at its 

 northwestern end (Stuart Knob, 9,300 feet [2,834.6 m.]) which is 

 formed of a remnant of one of the hard limestones of the Bosworth 

 formation. 



The measured section began at the southwest base and extended 

 around the point of the mountain into the large amphitheater on the 

 northeast side, and thence northwest to the summit of Stuart Knob. 



The strata of the main mountain dip slightly to the north-northwest 

 and those of Helena Ridge to the west-northwest, forming a shallow 

 syncline at the head of the amphitheater. This structure aids in giving 

 very fine exposures of the quartzitic sandstones of the Lower Cam- 

 brian at the base of the mountain to the summit of the section. 



Feet Meters 



UPPER CAMBRIAN 

 Bosworth Formation 



la. Gray and bluish-black limestone, with interbedded sili- 

 ceous layers and numerous small concretions 50 15.2 



Fauna. — 58n: Annelid trails and undescribed trilobites. 

 lb. Compact gray to drab siliceous limestone in layers 

 i inch to 6 inches (.6 to 15 cm.) thick, with inter- 

 bedded bands of dark arenaceous shale 45 i3-7 



