1894. PROCEEDINGS OF THE NATIONAL MUSEUM. 239 



Laramie. The Filicites Hebridka of Forlies is our Onoclea sensibilis. Tbo species of 

 (linlcgo, Taxiis, Sequoia, and (rli/2>fosfrohus correspond, and we liave now probably 

 found a Podocarpiis, as noted above. Tlie Flataniien HehrUlica is very near to our 

 great Fhitanusnohilis. CoryJuH MacQuarrii is common to both formations, as well as 

 Popuhis arctica and P. Richardsoiii, Avliile many of the other exogens are generically 

 the same, and very closely allied. These Ardtun beds are regarded by Mr. Gard- 

 ner as Lower Eocene, or a little older than the Geliudeu series of Saporta, and nearly 

 of the same age with the so-called Miocene of Atanekerdluh, in Greenland. Dr. G. 

 Dawson and the writer have, ever since 1875, maintained the Lower Eocene ago of 

 our Laramie, and of the Fort Union group of the Northwestern United States, and 

 the identitj^ of their flora with that of Mackenzie River and the upper beds of 

 Greenland, and it is very satisfactory to hnd that Mr. Gardner has iiide])endently 

 arrived at similar conclusions with respect to the Eocene of Great Ilritain. 



Dr. Dall is rather more cantious in adopting the Eocene age of these 

 beds. He says : * 



I have already pointed out the probability that, if Miocene at all, the leaf beds 

 of Greenland referred to would be synchronous with that geological epoch durino- 

 which the old Miocene warm-water invertebrate fauna of the Atlantic coast pene- 

 trated as far north as New Jersey. Since that time it is highly improbalile that any 

 temperate conditions, such as the flora would indicate for the Atane period, have 

 obtained in the latitude of Greeuland. In otliei- words, the Greenland beds are not 

 later than the old Miocene, though this does not preclude a n^ference of them to an 

 older horizon than the Miocenes for during the Eocene also the conditions in the 

 extreme north might have Itceu faxorabh^ to such a florn. 



In Alaska, at CtxdvS Inlet, a-f Uuga. Island, at Sitka, and at Nulato, in tlu" Yukon 

 Valley, we find the leaf beds of tint K(!nai group immediately and couCormabh- over- 

 lain V)y maTine beds eontiiiniug fossil shells, which are common ((» tlir Miocene of 

 Astoria., Oregon, and to niieldic .iiid soiith(Mti (,'alifornia. 



It is then certain tliat the Kenai h^af beds immediately prece<led and their depo- 

 sition terminated with the depression (probably moderate in A'ertical range), which 

 enabled the marine Miocene fauna to spread over part of the anteced(!ntly dry laud. 

 Further researches along the Alaskan coast will doubtless enable us to determine 

 whether the leaf beds themselves are underlain by marine Eocene beds or not. We 

 know that the Aucella beds underlie the Kenai series, but whether there are any 

 beds rei>resenting the mai'ine phase of the Ivteeue between them is yet uncertain 

 though very probable. 



What may be considered as reasonably certain is that the ])eiiod during which 

 in the Arctic regions the last temperate flora flourished was in a general way the 

 same for all parts of the Arctic. It would seem highly improbable that a temperate 

 climate should exist in the Spitzbergen and not at the same time in Greenland and 

 Alaska, or vice versa. If Alaska was covered by the sea at this time, we should 

 find a temperate marine fauna; if it was dry land, a temi)era,te flora; and so with the 

 other Arctic localities; and these indications should, it would seem, represent an 

 identical and synchronic phase of geological history in the Arctic regions. 



The distribution and character of this group have been somewhat fully discussed 

 because, up to very recently, authorities were practically unanimous in referring it 

 to the Miocene, a view which can yet be said to be definitely refuted. But when we 

 consider how the Eocene Astoria bed is innucdiately and (conformably overlain at 

 Ast(n-ia, by shales and sa-nds'tones, and that the latter rTonformably and immediately 

 in like manner overlifw the Kniai group, it must be romceded that the view that the 

 latter is probably of Eocene age docs not appear unreTTsonable. 



Bull. n. S. Geol. Survey, No. 8.5, p. 251, 



