DEVONIAN. 337 



wholly composed of corals, interstratified with some dolomitic beds. This limestone is well 

 exposed at the falls on Hay Kiver and also at the Ramparts, on the Mackenzie. In both these 

 places it is underlain by several hundred feet of greenish and bluish shales, alternating with thin 

 limestone beds. At the "Grand View," on the Mackenzie, the shales are hard and fissile and 

 are blackened and in places saturated with petroleum. At the Rock by the River Side and at 

 other places where the beds are tilted and older rocks exposed the middle division is underlain 

 by 2,000 feet or more of grayish limestones and dolomites interbedded occasionally with some 

 qup.rtzites. No fossils were collected from the lower part of this series, and rocks older than the 

 Devonian may possibly be represented in it. 



Representative collections of fossils, showing a mixture of Hamilton and Chemung forms, 

 were obtained from the upper part of the shales on Hay River, at a point about 40 mUes above 

 its mouth, and from the same horizon at the Ramparts, on the Mackenzie. The lithological 

 characters and the stratigraphical relations of the limestones at these two points, notwithstand- 

 ing the fact that they are separated by a distance of over 570 miles, are almost identical. The 

 fossil faunas also at the two points show similar close relations, the principal differences being 

 the presence of Khynchonella cuioides and Spirifera disjuncta at Hay River and of Stringocephalus 

 hurtini at the Ramparts. This might seem to indicate that the beds at the Ramparts are slightly 

 older than those at Hay River, but Mr. Whiteaves thinks that both are referable to the Cuboides 

 zone. 



Fossils collected from the Devonian of the Mackenzie basin by early expedi- 

 tions were described by Meek,®*^^' who gives an account of the history of exploration 

 and of the fossUiferous localities. Whiteaves ^^^ has discussed the collections sub- 

 sequently made by the Canadian Survey parties. He describes the Devonian 

 species from the Mackenzie represented in the museum of the Canadian Survey and 

 lists them according to localities from southeast to northwest. He then comments : 



An analysis of these lists shows that 22 of the species are found also in the Hamilton forma- 

 tion of Ontario or the State of New York. [List follows.] 



In the Mackenzie River district, however, the subdivisions of the Devonian system that 

 exist in the State of New York and Ontario are probably not recognizable, and there are strong 

 reasons for supposing that the whole of the fossils reported upon in these pages belong to the 

 "Cuboides zone." 



It is true that Khynchonella cuioides itself has so far been found only on the Peace and 

 Hay rivers, where it is invariably associated with Spirifera disjuncta (or verneuili), but other 

 fossils eminently characteristic of the Cuboides zone wiU be noticed in nearly aU the foregoing 

 lists of species from the Athabasca and its tributaries or from the Mackenzie. 



The paper concludes with a discussion of the Cuboides fauna and a comparative 

 Ust of 29 identical species from the Mackenzie basin and the European side of the 

 Atlantic. 



P 4-5. ALASKA RANGE AND SOUTHERN ALASKA. 



Devonian rocks are included in the Paleozoic complex that forms the western 

 slope of the Alaska Range, in the strike of the formations which occur throughout the 

 Yukon-Tanana region, but they have not been differentiated. ^"^"^ Middle Devonian 

 fossils have been found in a blue siliceous limestone at several localities. 



In the Copper River district the Nikolai greenstone, composed of volcanic flows, 

 resembles the Rampart group (Devonian) of the Yukon and is shown by Brooks ^"^ 

 to occur stratigraphically at a similar horizon. Later studies, however,^^^ have tended 

 to prove a later age (late Carboniferous or Triassic) for the Nikolai greenstone. 



48011°— 12 22 



