Quarterly Journal of the Geological Society of London/Volume 34/Notes on Fossil Plants discovered in Grinnell Land
In the vicinity of Discovery Harbour, where H.M.S. 'Discovery' wintered during 1875–76, a thick bed of lignite was found. The locality referred to is on the western shore of Robeson Channel, in about latitude 81° 45' N., and longitude 64° 45' W., north-west of Cape Murchison; the exact position is designated Watercourse Ravine in the Charts of the English Expedition.
This coal-bed has a thickness of from 25 to 30 feet, and lies in a depression, the foundation of which consists of the unconformably stratified azoic schists which constitute the chief mass of Grinnell Land. On the coal-bed rest immediately black shales and sandstones. The black, fine-grained shales, which very closely resemble the Taxodium-shale of Cape Staratschin on the Ice-fiord of Spitzbergen, contain many remains of plants, which were collected by Captain Feilden and handed over to me for examination. The coal-seam and the superincumbent beds of shale and sandstone dip to the east under the sea of Robeson Channel at an angle of about 10°. These beds are cut through by a stream which has formed a deep gully, wherein the strata are laid bare; whilst at different points on the upper strata rest beds of fine mud and glacial drift, which contain well-preserved shells of marine Mollusca (Saxicava rugosa, Astarte borealis, &c.) now found in the neighbouring sea. This glacial marine deposit is met with up to a height of 1000 feet above the present sea-level, and shows that the land was sunk beneath the surface of the sea subsequently to the deposition of the lignite and plant-bearing shales, but was again elevated more than 1000 feet. Very probably the lignite-bed and the accompanying plant-bearing shales are to be met with in other parts of Grinnell Land, although hitherto only proved to occur at the place indicated.
Captain Feilden only made two visits, as the plant-bearing nature of the deposit was not discovered until a very late period of the Expedition. This is much to be deplored, as the shales enclose rich botanical treasures.
Captain Feilden's collection contains 26 species; and of these, 18 species are known from the Miocene deposits of the Arctic zone. This deposit is therefore doubtless Miocene. It shares 17 species with Spitzbergen (latitude 76°–79° N.) and 8 species with Greenland (latitude 70°–71° N.). The Grinnell-Land flora consequently more closely approaches the Miocene of Northern Spitzbergen (which lies from 3° to 4° of latitude further south) than that of Greenland (situated almost 11° further south). With the Miocene flora of Europe it has 6 species in common, with that of America (Alaska and Canada) 4, and with that of Asia (Sachalin) 4 also.
Let us now examine these plants somewhat more closely. Of Cryptogamia we find only a couple of Equiseta, of which one species is Equisetum arcticum, which is found not uncommonly in King's Bay, at Spitzbergen (see my 'Flora foss. Arct.' ii. p. 31). It flourished probably, like its nearest ally Equisetum limosum, Linn., on the muddy shore of a sea or a river. In Grinnell Land as in Spitzbergen, the Coniferæ hold the first place. Ten species of these occur, belonging to four families—Taxineæ, Cupressineae, Taxodieæ, and Abietineæ. The Taxineæ are represented by the remarkable genus Torellia, of which the species Torellia rigida, Heer, must have been very abundant. This was previously known only from Cape Staratschin in Spitzbergen, where only a few fragments of leaves were found; now from Grinnell Land we have a great number of perfectly preserved leaves, which confirm the conclusions previously arrived at. It is, in fact, a conifer most nearly allied to the genera Phœnicopsis and Baiera of earlier periods. The leaves have the same form and texture as those of the Phœnicopsis of the Brown Jura (Oolitic); they are also traversed by numerous longitudinal nerves, and arranged in clusters. They differ, however, in having a channel enclosed by a rib. As the Phœnicopsis of the Jura forms a link with the Cordaites of the Carboniferous, so, on the other hand, it joins the Torellia of the Tertiary. This genus, however, is confined to the most northern portions of the globe. Amongst living Coniferæ Podocarpus (group Nageia), which genus was united by Parlatore with the Taxineæ, should stand next to Torellia.
The Cupressineæ are represented in Grinnell Land only by a Thuites (T. Ehrenswärdi, Heer?), fine twigs of which were found in King's Bay, Spitzbergen (lat. 79° N.), but has only reached us from Grinnell Land in the form of one small fragment which cannot be determined with perfect certainty. On the other hand, the leaf- covered twigs of Taxodium distichum miocænum, which is one of the most abundant plants of Grinnell Land, and appears in many varieties, are most beautifully preserved. Fortunately we have it in a state of bloom from this place as from Cape Staratschin, viz. the male flowers, which completely correspond with those of Spitzbergen. They show that this remarkable tree, now existing only in the south of the United States and in Mexico, lived and bloomed during the Miocene period almost as far north as 82°!
In Grinnell Land, as in Spitzbergen, the genus Pinus possesses the greatest number of species. These belong to 4 subgenera: 2 species belong to the Pines (Pinus in the strict sense of the word), 1 to the Spruce Firs, 1 to the Pitch-pine, and 1 to the Tsuga group. Of the Pines one species (Pinus Feildeniana, Heer), is represented by well- preserved seeds and by remains of needles which are very slender. This species is closely allied to Pinus strobus, L., and may be compared among fossil species to P. stenoptera, Heer, from Spitzbergen, and to P. thulensis, Steenstrup, from Iceland. Pinus polaris, Heer, is a second species, the needles of which are abundant. These needles are also known from Spitzbergen and Greenland. Excellently-preserved seeds of this species were discovered by Nordenskiöld in Spitzbergen.
It is a very interesting fact that in Grinnell Land two twigs of the Spruce (Pinus abies, Linn.) still covered with leaves were found. I had already received single detached leaves from Spitzbergen; with them there were seeds of this species, and, further, there was also found a scale of the cone (see my "Miocene Mora of Spitzbergen" in the 'Flora foss. Arctica,' ii. tab. v. fig. 35–49); so that the species could be determined with perfect certainty. We therefore see that our Spruce (Red Fir) was living during the Miocene period in Grinnell Land as well as in North Spitzbergen, and at that time doubtless extended as far as the pole, at least if any dry land then existed there. In Europe the tree did not then exist; hence very probably it had its original home in the extreme north, and has thence extended southwards. We first meet it in Europe in the Forest-bed of the Norfolk coast, and in the interglacial deposits of lignites in Switzerland. At that time, therefore, it had come into our regions, and has ever since formed a principal constituent of our forests. Its extreme northern limit is now in Scandinavia, latitude 6912° N.; and it is now spread over about 25 degrees of latitude, whilst during the Miocene period it was limited to the Arctic zone. The case is quite different with Taxodium distichum, the second species of tree which Miocene Grinnell Land had in common with the flora of the present day; for during the Miocene period it extended from Central Italy up to 82° N., and was spread over all portions of the northern hemisphere, whilst at present it is confined to a comparatively small area.
Tsuga forms a third subgenus of Pinus occurring in Grinnell Land, to which we must refer the Pinus Dicksoniana, Heer; small twigs covered with leaves, and one seed, were found, as at Cape Staratschin. The species resembles the American Hemlock-Spruce (P. canadensis). To these must be added some large needles which seem to indicate a Fir of the group of Pinus grandis and P. lasiocarpa.
The Monocotyledons are represented in Grinnell Land by reeds and fragments of leaves belonging to Phragmites œningensis, a species which has also reached us from Greenland and Spitzbergen, and shows that the damp localities were covered with large reeds; narrow leaves with a midrib, which lie along with them, indicate a Carex (C. noursoakensis, Heer), with which we are also acquainted from Greenland and Spitzbergen.
Of Dicotyledons Captain Feilden's collection contains 8 species belonging to 6 families—Salicineæ, Betulaceæ, Cupuliferæ, Ulmaceæ, Caprifoliaceæ, and Nymphæaceæ.
The Arctic Poplar (Populus arctica, Heer) is an old acquaintance, which one can trace over the whole Arctic zone, and which is one of its most abundant trees; of the two species of Birch, one (Betula prisca) is also abundant in high northern latitudes; and the occurrence of a pretty large piece of bark in Grinnell Land, and of a still larger piece in Spitzbergen, shows that the species formed trees of considerable size.
The second species of Birch from Grinnell Land (Betula Brongniarti, Ett.) is the only European species of plant from Grinnell Land which was not previously known from the Arctic zone.
The most abundant foliage-leaves of Grinnell Land belong to Corylus MacQuarrii, Forb., sp., which is spread over the whole Arctic zone and is nearly related to the living C. avellana, L. Very beautiful leaves of C. insignis, Heer, occur; this species I have also received from Greenland; and in the form of its leaf it resembles the American Hazel. An Elm (Ulmus borealis, Heer) is represented by a couple of leaves and a fruit, and a Viburnum (V. Nordenskiöldi) by several fragments of leaves. Both species are also known from Spitsbergen.
These trees and shrubs doubtless lived on the land, and covered the plains and hills of this far northern region with green; but that there also existed stagnant water is shown by a water-Lily (Nymrphæa arctica, Heer) of which the rhizoma, exactly agreeing with one from the Ice-fiord, Spitzbergen, was found. Here the leaves and fruit could also be identified (see 'Flora Arctica,' ii. tab. xiv. figs. 1, 2, 6, 7).
The thick lignite bed of Grinnell Land would indicate a large peat-moss, in which most probably a small lake existed. On the shallow bottom of this lake the great rhizomes of the Water-Lilies might spread; and from them the leaves would rise to the surface of the water. On the muddy shore stood the large reeds and the sedges (Carices), the Birches and the Poplars, the Taxodia with their graceful foliage, and the rigid-leaved Torelliæ. The drier spots and neighbouring chains of hills were probably occupied by the Polar and Feilden Pines (P. polaris and P. Feildeniana), by the Firs, the Hemlocks, and the Hayes-Spruce (Pinus Dicksoniana and P. Hayesiana). To these must be added the Elm and the Hazel bushes, whose fresh green foliage will have served to break the gloomy garb of the Pine-forest. This forest was no doubt inhabited by animals; yet hitherto only the elytron of a Beetle (Carabites Feildenianus, Heer) has been discovered lying with the plants. A further careful investigation of this important locality would no doubt produce more such remains, and also promise a further rich result in plants.
In the lignite itself we may expect to find the teeth and bones of vertebrate animals.
If we glance back at the facts communicated, we shall find that they confirm and extend the earlier results in a most satisfactory manner. As was to be expected, during the Miocene period there appear in this most northern portion of the earth, for the most part, the same species, with which we are already acquainted from Spitzbergen and Greenland; and it is highly probable that the same flora extended up to the Pole, and that, supposing dry land to have existed there, this latter was clothed with the same forest of coniferous and leafy trees.
That the flora of Grinnell Land approaches much more closely to that of Spitzbergen than to that of Greenland, is easily intelligible from the greater difference of latitude. The plant-bearing locality of Grinnell Land lies much nearer to the north-west of Spitzbergen (Ice-fiord and King's Bay) than to Disco and the opposite peninsula of Noursoak, which have furnished the Miocene plants of Greenland.
We have previously pointed out ('Flora foss. Aretica,' ii. p. 16) that the Miocene flora of Spitzbergen as compared with that of Greenland would seem to indicate a considerable climatic difference, inasmuch as a great number of more southern forms which Greenland possesses—such as Castanea, evergreen Magnolia, Prunus, Ilex, MacClintockia, and Coccolites—are wanting in Spitzbergen. The same holds good with regard to Grinnell Land.
On the other hand, the facts hitherto brought forward indicate no difference between Spitzbergen and the plant-bearing locality of Grinnell Land, lying from 3 to 4 degrees of latitude further north. It is true that the Miocene flora of Spitzbergen is very much richer, since we are already acquainted with 179 species belonging to it. This, however, is probably due to the fact that Professor Nordenskiöld and his comrades collected in Spitzbergen with great zeal and success during several expeditions, whilst the plant-bearing locality of Grinnell Land was only visited by members of the English Expedition on a few occasions. It is to be particularly noted that Taxodium distichum and a Water-Lily still appear in this place. The latter presupposes fresh water, which must have remained open during a great part of the year; and the Taxodium excludes an Arctic climate. Indeed it only exists still in North Germany by cultivation, and Professor Schübeler's repeated attempts to cultivate it at Christiania were in vain (comp. 'Pflanzenwelt Norwegens' by Schübeler p. 148). Representatives of plants now living exclusively in the Arctic zone are wanting among the species of Grinnell Land; but, on the other hand, certainly most of the genera still extend into the Arctic zone, viz. Equisetum, Pinus, Phragmites, Carex, Populus, Betula, Corylus, Ulmus, and Nymphæa. Of these, however, only Equisetum, Carex, and Populus extend beyond latitude 70° N.; the remaining genera cease earlier. Pinus abies, L., reaches latitude 69° 30' N.; the genus Phragmites, in P. communis, in Finmark, to latitude 69° 45' N.; Corylus, in C. avellana, to latitude 67° 56' N.; Ulmus, in U. montana, in Norway, to latitude 66° 59' N., and cultivated to nearly latitude 70° N.; Nymphæa, in N. alba, in Scandinavia, to latitude 69° 11' N. These genera therefore appear in Grinnell Land at from 12 to 15 degrees higher latitude.
P.S., 20th Jan., 1878.—Mr. Edward Moss, Surgeon of H.M.S. 'Alert,' collected some fossil plants in the same spot as Captain Feilden, and has submitted them to Prof. Heer's examination. They belong to 14 species, 4 of which are wanting in Captain Feilden's collection. We therefore know at present 30 species of Miocene plants from Grinnell Land. Descriptions and figures of all the species will be published in the fifth volume of the 'Flora fossilis arctica.'
Discussion.
The President, after expressing his sense of the value of Prof. Heer's paper, referred to the great difficulties under which Capt. Feilden laboured during his visit to the Arctic region, and remarked that nevertheless he had realized results of very considerable importance. He referred to Prof. Heer's notion that a migration of certain plants had taken place since Miocene times from north to south, and pointed out that the existing North-American flora more resembles the Miocene than its own Pliocene flora. An examination of the Echinodermata brought home by the Arctic Expedition had led him and Mr. Sladen to the belief that these also furnish indications of there being a polar zone of Echinoderms.
Capt. Feilden exhibited a photograph and gave some account of the locality from which the plant-remains were brought. He stated that shales and sandstones similar to those overlying the lignites were found lying directly on the older schists in other neighbouring valleys, and that in some instances fragments of lignite occurred in them, and suggested that probably the whole of the valleys here were at one time occupied by deposits of the same age.
Prof. Ramsay remarked that after listening to all that had been done in the investigation of Arctic floras, it was impossible not to feel convinced that we only require to get hold of the right clue in order to make out a great deal. He said that he could not believe that plants such as Sequoias, Figs, and Vines could live through the long night of an Arctic winter and flourish again the following summer. He thought that the gradual accumulation of palæontological facts was gradually leading to a general opinion that there must have been a change in the direction of the axis of the earth with respect to the sun's light; and if, as he understood, Prof. Heer believed that plants had spread from north to south, it seemed to him that this was strongly in favour of a change in the direction of the polar axis.
Mr. Evans said that Capt. Feilden had referred to a dying-out of species as we advance towards the pole, and suggested that if this be real, it may be due to our explorations northwards lying in the same direction as that taken by the pole in its movement southward. The variation of level mentioned to the extent of 1000 feet, might throw some light on the question, as it might be due to a change in the position of the nucleus of the earth with regard to its surroundings.
Capt. Sir George Nares referred to the presence of vast fluviatile deposits close to the bed of lignite.
Dr. Murie thought that too much stress was laid upon the influence of the sun's light in this question, and referred to the fact that tropical plants are preserved and flourish in St. Petersburg in spite of the long dark winter. He suggested that changes in electrical conditions might have some influence on the possibility of the existence of life at the poles.
Prof. Hughes inquired how far round the arctic circle we can find evidences of such changes as are assumed. If the changes in the position of the pole were geographical, it was clear that the Miocene vegetation could not approach the pole all round at the same time.
Mr. Woodward remarked that the onus probandi rested, not with the geologists, but with the mathematicians, upon whom it was incumbent to show how plants could grow at the points where their remains were found, supposing the position of the earth to have remained the same.
Mr. Sollas remarked that Prof. Heer had already shown that the Miocene flora diminished both in genera and species when traced from Switzerland northward, in such a manner as to indicate that while the temperature of the northern hemisphere was generally higher in Miocene times, yet it decreased towards the north pole very much as it does now, only more slowly. Capt. Feilden's remarks on the thinning-out of species from Spitzbergen to Grinnell Land were quite in accordance with this. It thus certainly appeared to him that it was not the geographical position of the poles, but the climatal conditions of the polar regions which had undergone a change. As regards a higher temperature, Dr. Croll's theory would account for that. As regards the necessity for light, it seemed to him that a long winter merely meant for the arctic plants a longer sleep. The light of a short summer would reach the ground unaffected by the absorptive action of aqueous vapour, which would filter out a good deal of the non-luminous heat-rays. In high northern latitudes heated by warm currents of water, we should have produced during the Miocene times natural conditions very similar to those produced artificially in the greenhouse of St. Petersburg: aqueous vapours would furnish a very efficient substitute for glass; and oceanic currents would serve for a warming-apparatus.