222 INDEX TO THE STRATIGRAPHY OF NORTH AMERICA. 



may be added an unknown thickness beneath the sea. Low ^^ states that the 

 strata range in age from "Galena-Trenton to Lower Helderberg." 



Q 3-4. SEWARD PENINSULA. 



Kindle has contributed the following note on the Silurian and Ordovician of 

 Seward Peninsula: 



The Port Clarence limestone furnished fossils which were determined as Silurian and 

 Ordovician. Recent collections from this hmestone show the presence of both Cambrian and 

 Ordovician faunas and indicate that the fauna previously considered Silurian is of late Ordo- 

 vician age. 



B-T 10-30. ARCTIC ARCHIPELAGO. 



Large areas in the "Arctic Archipelago are colored as Silurian (upper Silurian or 

 Gothlandian) in accordance with the doiriinant character of the fossils collected by 

 several expeditions. Detailed references and descriptions are given in Chapter V 

 (pp. 265-266) . These Silurian strata, however, are in certain localities and probably 

 as a rule underlain by Ordovician. Dawson ^^^* summarizes: 



In a paper printed in the report of the British Association for 1855 J. W. Salter states that 

 the Silurian fossils obtained up to that time showed a uniform horizon of Upper Silurian hme- 

 stone stretching from near the entrance to Barrow Strait to Melville Island and far to the 

 south along Prince Regent Inlet and argues therefrom a wide extent of circumpolar land in 

 lower Silurian (Cambro-Silurian) times. In this he was followed, two years later, by Sir R. 

 Murchison," who writes: "I am led to beheve that the oldest fossiliferous rock of the Arctic 

 regions is the Upper Silurian." Though the Upper Silurian beds undoubtedly occupy a great 

 part of the American polar region, characterizing the "South of North Devon and nearly all 

 the islands south of Melville and Lancaster sounds, including the south of Banks Land, Prince 

 of Wales Land, King William Land, North Somerset, Boothia, Felix, etc.,"* the occurrence of 

 Lower Silurian (Utica) fossils in Frobisher Bay, as shown by Hall's collections, on the shores 

 of Kennedy Channel, as determined by Etheridge, and the occasional discovery of Lower 

 Silurian forms in the regions above referred in a general way to the Upper Silurian prove that 

 the gerieraUzation made by Salter and Murchison, on the evidence of less complete collections, 

 can not now be admitted and that the limestones of the Arctic represent probably the whole 

 of the Silurian [Lower and Upper], and possibly part of the Devonian.* Heer'= enumerates 

 the following places, besides those above particularly referred to, as yielding Lower Silurian 

 types: North Devon, ComwaUis Island, Griffith Island, west coast of King WiUiam Land, 

 Boothia. 



Dawson's inference was verified in 1900 by Schuchert,"^ who studied new col- 

 lections from Sillimans Mount, at the head of Frobisher Bay, and extended the 

 basis of correlation with other areas in the Arctic Archipelago. After enumerating 

 localities, Schuchert says: 



From the foregoing description of localities, it appears that middle Lower Silurian horizons 

 are very extensive in eastern Arctic America. Such are known in places on either side of Hud- 

 son Strait, Frobisher Bay, the interior of Baffin Land, and to the north of this land at various 

 locahties between latitudes 79° and 80° north. As far as known, these strata unconforinably 

 overlie very ancient crystalline rocks and are in turn overlain by Upper Silurian beds of Niagara 

 or WenJock age. Lower Cambrian rocks are found in southern Labrador, but ia the region of 



" Appendix to McClure's voyage, p. 402; Siluria, p. 440. 

 6 Fielden and De Ranee, Quart. Jovir. Geol. Soc, vol. 34. 

 - Flora Fossilis Arctica, vol. 1, p. 24. 



