Occasionally a student like Nathorst (1911) did not let his imagination get the better of him and called to mind the wonderfully rich life of the Arctic seas of today, but for the most part. Recently, Kirk2 collected some evidence for the abundance of the present sea. 82 also comforts meteorologists who are confronted with the traditional view of the lack of climatic zones for most eons of Earth's history.
I propose to review what we know about the past distribution of plants in the Arctic, after which I will attempt to evaluate what this means between climates. Beneath the coal seams is subsoil with roots in place and the plant remains show no sorting - that is, delicate material is mixed with stems and branches of all sizes - both facts conclusively indicating that the bulk of the material was not transported, but grew in the immediate vicinity. For example, there are now two species of Equisetum and one of Lycopodium found within 10 degrees of the pole in northwestern Greenland (Ostenfeld, 1925).
The fact that many Devonian plants were palustic also lends strength to the conclusion, which I have elaborated elsewhere, that these Devonian plants, although ancient and simple, were not primitive and ancestral, but were reduced descendants of more organized ancestors . In this most extensive culm flora known, there are no distinct Arctic species, nor are there any genera which are not common to floras of the same age from lower latitudes. For example, Dadoxylon beinertianum Endlicher from Silesia, Dadoxylon Tchicliatclicffianiuin Endlicher from Russia, and Dadoxylon vogesiacum Unger from the Vosges, all of the same age as the Spitzbergen species, show distinct seasonal rings, but other contemporaneous European species do not.
Palustrine types predominate, as in the case of the Devonian, and more than half.
NO. 6 PAST CLIMATE OF NORTH POLAR REGION BERRY
8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82
LOWER CRETACEOUS
UPPER CRETACEOUS
NO. 6 PAS! CLIMATE OF NORTH POLAR REGION BERRY
10 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82
TERTIARY
12 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 and described a great many more species than he should have done
NO. 6 PAST CLIMATE OF NORTH POLAR REGION BERRY 1 1 }
14 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 The so-called Kenai flora of Alaska was originally described by
NO. 6 PAST CLIMATE OF NORTH POLAR REGION BERRY 1
The extant flora most similar to that of the Jackson does not extend above Latitude 26 North, and then only under particularly favorable situational conditions in relation to warm ocean currents. The flora of the Jackson, moreover, was a coastal flora, and I have not the least doubt but that if Mississippi Bay had extended five degrees farther north, its shores would have been clothed with the same Jackson flora, for at that time similar flora in the Paris Basin in Latitude 49° North,.
EXISTING ARCTIC FLORAS
NO. 6 PAST CLIMATE OF NORTH POLAR REGION BERRY IJ This brief statement will be sufficient to indicate that there are other
EXISTING ARCTIC CLIMATES
SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 of air 4,000 meters deep over the whole of Europe on an average
NO. 6 PAST CLIMATE OF NORTH POLAR REGION BERRY 19 ceived ocean waters from the Pacific or across Eurasia from ancient
20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 tion that the flora of the Carboniferous grew in a supertropical
In nature, the right species is subject to the historical factor that there were ancestors in the region or in the region that provided access to the specific region. In the present-day tropics, certain palms reach heights of almost 3,000 meters, such as in the wet parts of the northern Andes (Ceroxylon, Geonoma, etc.). The genus Ficus, to which the cultivated fig belongs, has over 600 extant species in a wide variety of habitats, and probably as many fossil species, dating back to the early Upper Cretaceous.
I have seen it in the subtropical temperate zone in Bolivia, and Weberbauer1 records an altitude range for it through Peru to 8,255 ieetm. Cinnamomum is the genus for some members of which the names cinnamon tree and camphor are used. The New World species are practically confined to the tropics, but in the Old World there are distinct temperate species in southern Europe and eastern Asia.
It has spread wild in Louisiana, and characteristic fruits occur in the Pleistocene of the Atlantic Coastal Plain as far north as Long Branch, New Jersey. A third source of error is the common assumption that because a particular type of plant has its home in the equatorial zone, it is necessarily a tropical plant. The species most often alluded to in the Arctic fossil flora as indicative of a once tropical climate are the tree ferns.
22 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 52
NO. 6 PAST CLIMATE OF NORTH POLAR REGION BERRY 27,
EXPLANATION OF PAST ARCTIC CLIMATES
24 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82
I believe, by Lyell, and in its more general application has recently been placed on a scientific basis by Brooks, with whom I am in perfect agreement to the extent of evaluating these as important factors, but also in my firm belief that armchair philosophy with his. Climate, in a uniformitarian geology, occupies a somewhat anomalous position, which the scientific world has been slow to admit, namely that the history of the human race lias been conducted under climate. Man evolved after the relative height and the great expansion of the continents that ushered in the Pleistocene glaciation, and therefore what is normal in human experience.
Thus, although we recognize that the climatic factors and the meteorological elements are the same now as ever, their combination to form actual climates depended on a great number of factors. It may be noted parenthetically that numerous theories of the causes of, or descriptions of, geological climates have been advanced by students ignorant of meteorology, and also usually ignorant of the relation of organisms to their environments, and the last is striking where from Kdppen & Wegener's recent DieKlimate der geologischen Vorzeit (1924). In an attempt, some years ago, to explain the extension of floras almost to the poles during the late Eocene, I relied mainly on the submergence of continental areas in the middle Eocene and the resulting free oceanic connections at that time between equatorial and Arctic waters, indicating that these Arctic floras were coastal floras and therefore under the regime of an oceanic climate.1 Essentially the same explanation was independently given in relation to Jurassic climates a few months later by Kerner presented by von Marilaun.2 An.
Therefore, a confluence of minor factors sufficient to cause a tipping in one direction or the other, that is, toward glaciation or melting, would be sufficient to induce a broad polar expansion. This would mean profound changes in the distribution of barometric pressure and consequent wind circulation, and indeed in all the elements that make up the climate. This would mean that e.g. in western Greenland, where the most extensive late Eocene arctic flora has been found, the present glacial anticyclonic winds would be replaced by westerly or southwesterly winds blowing from the relatively warmed waters of Baffin Bay, and this will satisfactorily explain the details. of the floral facies.
This does not mean that a tropical climate would exist in the Arctic or that the region would not be affected by ice in the winter season. It seems to me that they are completely unaware of the large amount of modern work on the distribution of marine organisms; and their ideas as to the climatic significance of a trilobite, eurypterid, or ammonite are merely a tradition inherited from the distant past, when all foreign organisms were associated with a torrid climate. Jeffrey, for example (Anatomy of Woody Plants, Chapter XXX, 1917), states that the older age is the warmer climate, and that there has been a gradual and progressive cooling throughout geological time; that the organization of secondary wood in extinct plants provides the most reliable evidence of climatic conditions; that growth rings appeared in high-latitude forests toward the end of the Paleozoic; that growth rings were developed in ten degrees in the Triassic.
There is no geological or paleontological evidence showing a progressive cooling of the climate during geological time, and the Permo-Carboniferous glaciation was certainly more extensive than the Pleistocene one. They have been inclined to use the present distribution of the imagined or real relatives of their fossil forms if temperature were the only factor in the environment, and have stopped at the geographical display, with the apparently simple belief that all lands in the equatorial zone were at sea level and humid tropical. A sojourn in the arctic climate below the equator on the spine of South America would do much to correct this misconception, as would some experience in the temperate rain forests of various regions.
28 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 not clone so although I did publish such a map for the Eocene in 1922
NO. 6 PAST CLIMATE OF NORTH POLAR REGION BERRY 20
CONCLUSIONS
