454 



NA TURE 



{Sept. 5, 1889 



Naturally, the species named also appear in this collection. 

 The later strata from the fir period are, according to Kurck, dis- 

 tinguished by a quantity of leaves of the mountain elm [Vlmjcs 

 montana). Leaves of hazel, birch, aspen, &c., are also found ; 

 •whilst', for the fir>,t time, leaves of the lime ( Tilia parvi- 

 folia) are met with, but very rarely. In this stratum Kurck has 

 also found the common bracken {Pteris aquiiina) and meadow- 

 sweet {Spima tilmaria). Some leaves of the alder he believes 

 to be still younger. 



Besides the species named — which are all found with rema'ns 

 of the fir — are some others. Already in Nordenskiold's col- 

 lection notice was attracted to portions of a stratum in which 

 the fir was absent, and which in a measure differs in appearance 

 somewhat from the rest of the tuff. These portions contain 

 leaves of the mountain ash, the common oak {Querais pedtincu- 

 lata), viz. hazel, lime, salix, and birch. This stratum has been 

 re-discovered by Kurck, and is, as might be expected, younger 

 than those named. It may be added that, according to earlier 

 writers, leaves of the maple {Acer platanoides) have also been 

 found at Benestad, but latterly none have been discovered. 



It would seem, then, that there is at Benestad a counterpart to 

 the Danish aspen, fir, and oak periods ; but we cannot quite say 

 that as regards the second period. There is, for instance, nothing 

 to prevent the fir having vegetated, through some accidental 

 causes, at Benestad, even during a part of the oak period. This 

 is the more likely as we find the tree at the present day in Northern 

 Scania. If, therefore, on the one hand, it is certain that the elder 

 pine strata at Benestad belong to the true fir period — the time 

 iiefore the immigration of the oak — it cannot, on the other, be 

 denied that the younger section of the fir strata may have been 

 deposited already when the oak immigrated thither. That some 

 of the fir-bearing strata must have been deposited relatively late 

 seems evident from the presence of such plants as dogwood, 

 hawthorn, elm, &c. However, the problem will no doubt be 

 final'y solved when once the peat-bogs of the province have 

 been palseontologically examined. 



Of the beeches and hornbeams {Carpinns hettdtis), now com- 

 mon in the district, there are no traces in the strata, and although 

 the springs still yield plenty of water, there appears to be no 

 deposit of calcareous tuff whatever. Thus, all we are really 

 able to say respecting the palaiontological remains in the fir 

 period at Benestad is that these plants immigrated before the 

 beech, and, most probably, even before the oak, and that all of 

 them came from the south-west. 



Respecting the flora which flourished in Scania previous to 

 the aspen and fir periods, we know its characteristics through the 

 vegetable remains in the fresh-water clays of the province. They 

 display a rich Arctic flora, comprising Dryas cctopetala, Salix 

 polaris, herbacea, reticidata, Betiila nana, Oxyria dlgyna, &c. 

 An animal fossil must also be mentioned, only recently found 

 among them, viz. Apus qlacialis, now common in Spitzbergen 

 lakes, but which in Scandinavia is not found south of the lakes 

 in the Dovre Mountains. 



In proportion as the inland ice melted, the Arctic flora, 

 so rich in varieties, advanced, but as the climate became 

 milder this flora was replaced by the forest vegetation immigrat- 

 ing from the south, and, at all events at Benestad, the trees 

 followed each other in the same succession as in Denmark, viz. 

 aspen, fir, oak, whilst the beech immigrated considerably later. 

 It is most probable that the forest vegetation followed in the 

 same order in the whole of Southern Sweden, but we do not 

 know this with certainty. For we still know too little respecting 

 the remains of plants in the peat-bogs of Southern Sweden. 

 That we are far behind in this respect is chiefly due to the cir- 

 cumstance that in Denmark the peat-bogs are turned largely to 

 profitable account. 



Of the calcareous tuff" strata in the province of West Gothia 

 we know unfortunately very little. They are, however, small in 

 extent, and contain only remains of trees still found in the neigh- 

 bourhood, viz. hazel, salix, and aspen. Near the Eskedal railway 

 station there is certainly a very large deposit, but not formed of 

 continuous tuff", but of loose calcareous debris, which does not 

 retain imprints. 



In East Gothia we have two calcareous formations, one near 

 Vreta cloister, which appears to be of a rather recent date, as it 

 contains salix, hazel, oak, and lime. The other, north of Vad- 

 stena, is, however, much older, and therefore of great interest. 

 This contains, among other remains of a pure Alpine plant, 

 Dryas octopctala (L.), which we already know from the Scania 

 fossil glacial flora, besides dwarf birch {Bctiila nana), and 



perhaps also Bdtila intermedia. There are also leaves of several 

 varieties of willow, birch [Betulaodoratd], crowberry {Empetrum), 

 Vaccinium tilii^inostini, and fir needles. The discovery of Dryas 

 in this locality is of the highest interest and importance, as it 

 leads us to hope that we may discover in other parts of Sweden 

 between Scania and Jemtland remains of an Arctic flora, which, 

 judging from the discovery referred to, must, at all events partly, 

 have advanced from the south through the whole country. For- 

 merly we did not possess a single pala:ontological proof from this 

 part of Sweden in support of this assump'ion. The discovery 

 is also of great interest in another respect, inasmuch as it shows 

 that Lake Vettern must have become separated from the Baltic, 

 with which it was once connected, at a time when the climate 

 w as Arctic — an assumption in full accord with Prof. S. Loven's 

 discoveries respecting the Arctic Sea fauna that to the present 

 day is found at great depths in this lake. 



The Jemtland strata have of late been examined by Herr A. 

 F. Carlson. This province is rather rich in calcareous tuff de- 

 posit?, some tv\enty localities having already been discovered. 

 Here, too, the first forests appear to have consisted of aspen, 

 birch, chiefly Beltila odorata, and fir, of which latter remains 

 have been found in several places. In four localities Dryas 

 octopctala have been found, and in two Salix reticulata, both 

 of the Arctic flora. As the former were found at Fillsta 

 and Digernas, in Sunne parish, and the other at Semla, in 

 Morsils parish, it; would appear to be proved that the Alpine 

 flora of jemtland formerly had a far greater extension within 

 the province than at present, and that at that period it reached 

 as far as the basin of Lake Storsjo. Without doubt an 

 examination of the fresh-water clays of the province would go to 

 show that the Alpine flora formerly coveied the whole of Jemt- 

 land. The tuff strata which contain such remains were de- 

 posited a little later, whilst the Alpine flora was in process of 

 being displaced by the forest vegetation. 



The remaining plants that have been found in Jemtland are 

 Dutch rush {Equisetuni hyeniale), salix, i-everal varieties of 

 willow, dwarf birch, Bettcla intermedia and alpestris, Alnus 

 incana, crowberry, mountain ash, Sorbus auctiporia, V^accinium 

 tdiginosum, and sea buck' horn {Hippophae rhamnoidcs). 



From the province of Angermanland we know two tuff de- 

 posits, near each other, but the paljeontological remains are few 

 and badly preserved. Here have hitherto been found only some 

 lichen, jjfir, birch, salix, and willow. 



In Asele, Lappmark, between Lingfors and L^ngsile, there 

 are two deposits — as far as we know the northernmost in Sweden. 

 Both are rich in leaf imprints, and thanks to Colonel N. Sjoberg, 

 of Asele, the National Museum has obtained specimens. The 

 species are certainly not numerous, but they are well preserved, 

 and consist of lichen, leaves of fir, birch, aspen, salix, some 

 willows, and Hippophae rhamnoides. 



As I have already stated, leaves of this plant have also been 

 found in a spot in Jemtland situated more than 1500 feet 

 above sea-level. Here the leaves are found in common with re- 

 mains of Dryas, but whilst the latter now has to be sought high 

 up in the mountains, the former is, on the contrary, only found 

 by the coast. It is found along the shores of the Baltic, from 

 Roslagen (near Stockholm) to Vesterboiten in the north, and 

 the thorny shrub, with its whitish silvery leaves, and yellow or 

 chrome-coloured sour berry-like. fruit, here goes by the name of 

 haf-thorn {i.e. sea thorn). In other parts of Central and Northern 

 Europe where this shrub grows, it is also a coast plant, but it is 

 found beside the glacial rivers of the Alps ; and its former 

 existence in the localities named in Norrland— right in the 

 heart of the country, high above the sea, together with other 

 Arctic plants— shows indisputably that here also it was origin- 

 ally an Arctic plant. But whilst Drya^, Salix reticidata, Sec, 

 were forced northwards by the immigrating forest flora, this 

 plant, on the contrary, found a place of refuge on the sea- 

 shore, where it flourishes to the present day. It seems, indeed, 

 hardly credible that two plants now so widely separated, geo- 

 graphically, as Dryas in the high mountains and Hippophae by 

 the Baltic shore, once grew side by side in the heart of the 

 country. 



Having dealt with the proofs respecting the former extension 

 of the Swedish flora furnished by the pakeontological remains of 

 the calcareous tuff strata, I purpose to touch upon an equally 

 important point, viz. that the spruce immigrated compara- 

 tively late. In no single tuff deposit has trace been found of 

 this tree, and this circumstance is too uniform throughout to be 

 a matter of accident. Especially peculiar are the conditions in 



