244 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



it thins rapidly eastward and changes in character to the northwest, 

 and has not been recognized in the Glacier Lake section. How far 

 it extends to the southeast is unknown. 



Stratigraphic relations. — -The upper limit of the Bos worth at Mount 

 Bosworth is clearly defined by the abrupt change from its thick layers 

 of gray magnesian limestone to the -oolitic limestones of the Paget 

 formation. The base is readily distinguished from the shallow water, 

 estuarian-like deposits of the Arctomys formation. 



Fauna. — I have seen only a few fragments of trilobites and an 

 O bolus from the Bosworth formation. 



Sullivan Formation. Walcott, 1919, 1923' 



Type locality. — In the cliffs on the north side of Glacier Lake 

 Canyon, east of southeast branch of Lyell glacier and south of Mount 

 Sullivan. 



Derivation of name. — From Mount Sullivan. 



Character. — This is largely an arenaceous and siliceous shale with 

 much interbedded, compact, hard, gray, and in the lower half, oolitic 

 limestones. 



Thickness. — The only section measured gave a total thickness of 

 1,440 feet (438.9 m.). 



GeograpJiic distribution. — Known only at Glacier Lake and the 

 headwaters of the Saskatchewan River drainage, but it may be that 

 when an areal geologic map is made the Sullivan may be traced into 

 'some Upper Cambrian formation of the Sawback Range and the Kick- 

 ing Horse section. To the northeast of the Castleguard River and to 

 the south of Mount Castleguard the characteristic erosion of the 

 Sullivan shales and interbedded limestones is finely shown in the 

 sharp ridges and points rising above the alplands. The formation has 

 not been recognized in the Robson Peak District. 



Stratigraphic relations. — The top of the series of arenaceous shales 

 was taken as the summit of the formation. This line is clearly outlined 

 beneath the cliff formed by the compact, hard limestone at the base 

 of the Lyell. The lower boundary is even jnore distinctly seen 

 where the shales rest on the light gray laminated limestones of the 

 Arctomys formation. 



Fauna. — This formation contains a Crepicephalus fauna and hence 

 is to be correlated with the Sherbrook and Paget formations. 



^ Smithsonian Misc. Coll., Vol. 67, No. 8, p. 461. 



