i8o 



very dense, so that they weather into compact angular 

 fragments. The beds in this series become very highly 

 sheared in the Beaverfoot valley and the range to the 

 west. 



On both paleontologic and lithologic evidence the 

 boundary between the Cambrian and the Ordovician in 

 this district is placed at the top of the Ottertail limestone 

 and at the base of the Goodsir shale. 



Cambrian-Ordovician contact in Mt. Goodsir. The gray rock is the Ottertail lime- 

 limestone, overlain by the dark-colored Goodsir shales. 



Fossils were found near the base of the Goodsir forma- 

 tion at several localities, and have been determined by 

 Walcott. The following new species have been identified 

 from this series. : — 



Obolus mollisonensis. 

 Lingulella? allani. 

 Lingulella moosensis. 

 Ceratopyge canadensis. 



The presence of the Ceratopyge fauna places this forma- 

 tion at the base of the Ordovician, corresponding to the 

 horizon of the Ceratopyge shale in Sweden. 



The sedimentary series from Mt. Whyte to Goodsir, 

 inclusive, were included by McConnell in his Castle 

 Mountain group. 



