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Darwin Correspondence Project

From Oswald Heer1   1 March 1875

Mein geehrtester Herr!

Ihre freundlichen Zeilen vom vorigen Jahr, die ich Ihnen, obwal spät, bestens verdanke, ermuthigen mich Ihnen den dritten Band meiner Flora fossilis arctica zu übersenden u. demselben einige Zeilen vorauszuschicken.2 Ich habe das Buch einer Sendung an unsern gemeinsamen Freund, Dr. Hooker,3 beigelegt u. hoffe, dass dasselbe in nächster Zeit Ihnen zukommen werde. Es enthält dasselbe eine Darstellung der Kreide=Flora der arctischen Zone, welche theils in Grönland zwischen 70. u. 71o N. Br., theils in Spitzbergen bis 78o N. von Prof. Nordenskiöld4 gesammelt worden ist. Glücklicher Weise wurde in Grönland eine ältere Kreideflora, welche aber wahrscheinlich dem Urgon angehört, zugleich aber auch eine jüngere Flora, die ins Cenoman einzurechnen ist, entdeckt. Die erstere besteht fast ausschliesslich aus Cryptogamen (voraus Farn), Cycadeen u. Coniferen u. hat ein Subtropisches Gepräge.5 Von angiospermen Dicotyledonen konnte eine einzige Art nachgewiesen werden, ein Populus, der zu einer Gruppe von Pappeln gehört, die in der obern Kreide u. im Tertiär in mehreren Arten erscheint u. in der Pop. euphratica den ähnlichsten lebenden Repraesentanten hat.6 Es ist diess die älteste, bis jetzt bekannte dicotyledon. Pflanze. (natürlich mit Ausschluss der Gymnospermen, welche von den ächten Dicotyledonen sehr verschieden sind).7 Es fehlen in Europa die Dicotyledonen in der untern Kreide ebenfalls; dagegen treten sie in der obern Kreide u. zwar schon im Cenoman, in Europa u. Amerika in grosser Verbreitung auf, u. ebenso erscheinen sie zu dieser Zeit in Nordgrönland u. zwar nicht etwa nur in einzelnen wenigen Typen, sondern in einer ganzen Reihe von Arten, welche Familien angehören, die im System weit auseinander liegen, wie Pappeln, Ficus, Myrica, Diospyros,—Araliaceen, Magnoliaceen, Myrtaceen, Leguminosen u.a.m.8 Mehrere dieser Familien sind nicht allein in den Blättern, sondern auch in den Früchten uns erhalten, so Ficus, Myrica, Panax,9 Magnolia.— Es mag nun allerdings sein, dass einzelne dieser Gattungen schon in der untern Kreide ihren Anfang nahmen u. vielleicht da noch entdeckt werden. Allein wenn wir auch mit der untern Kreide die Dicotyledonea beginnen lassen wollen, müssen wir doch zugeben, dass diese Abtheilung des Pflanzenreiches, die die Hauptmasse der Vegetation der jetzigen Zeit bildet, erst relativ spät auftritt u. in (geologisch gesprochen) kurzer Zeit eine grosse Entfaltung erhielt. Vom Devon an bis zur Kreide haben wir einen unendlich langen Zeitraum, während dessen, so viel wir bis jetzt wissen, die Pflanzenwelt nur in Cryptogamen, Coniferen & Cycadeen und einigen wenigen Monocotyled. erscheint.10 In der obern Kreide aber geht auf einmal eine grosse Veränderung in der Pflanzenwelt vor sich u. überall wo bislang fossile Pflanzen in derselben gefunden wurden: in Mähren, Boehmen, Sachsen, am Harz, bei Quedlinburg, in Westphalen, bei Aachen, in Südfrankreich, in Rüssland, in Grönland, in Nebraska u. im tropischen Afrika (von wo ich neuerdings von Dr. Schweinfurth11 aus der obern Kreide Diospyros-Früchte erhielt), erscheinen nun zum ersten Mal die (angiosperm.) Dicotyledonen u. geben in relativ kurzer Zeit der Pflanzenwelt eine ganz andere Physiognomie. Im Eocen haben wir dann eine weitere Entwicklung dieser Formen. Es hat eine unendlich lange Zeit gedauert bis die ersten Dicotyledon. entstanden u. wie diese gebildet, fand eine rasche Entfaltung derselben statt.

Damit scheint mir eine andere wichtige Erscheinung in Verbindung zu stehen. Abgesehen von den kleinen Säugethieren des Jura, die wahrscheinlich von Insekten gelebt haben, treten die omnivoren u. herbivoren Mammalia erst im Eocen auf. Wir dürfen wohl sagen, dass in allen frühern Perioden, von dem Carbon bis zur mittlern Kreide die Pflanzen für die Säugethiere keine Nahrung geliefert haben würden. Keine Säugethiere leben von Farn, Equiseten u. Lycopodien u. auch die Cycadeen u. Coniferen12 geben für sie eine sehr kärgliche Nahrung, deren sich die der Jetztwelt nur im Nothfall u. bei Hungersnoth etwa bedienen. Die Hauptnahrung, die sie aus dem Pflanzenreich beziehen, liefern die Dicotyledonen u. die Gramineen.13 Nun treten allerdings einzelne Gramineen mit den Dicotyledon. Schon in der Kreide auf und somit entstanden auch schon zu dieser Zeit die Lebensbedingungen für dieselben, doch müssen sie schon eine gewisse Verbreitung gehabt haben, um als Grundlage ihres Lebens dienen zu können. Da schon im Untereocen Paridigitata u. Imparidigitata14 vorkommen, mögen wohl einzelne Typen schon in der obern Kreide entstanden sein, doch zeigen uns die Säugethiere im Eocen dieselbe Erscheinung, wie die Pflanzen in der obern Kreide, indem auch bei ihnen in dieser Zeit eine auffallend rasche Entwicklung eintrat. Wie zur Zeit der obern Kreide, so bestand auch zur Eocenzeit in Europa die Pflanzenwelt grossentheils aus Baümen u. Sträuchern mit steifen, lederartigen Blättern es fehlten noch die von Gräsern gebildeten Wiesengründe u. das aus weicherm Laub gebildete Buschwerk. Die Säugethiere werden daher vorherrschend von Pflanzenwurzeln u. von den Früchten den Bäume gelebt haben, von den Früchten von Ficus, Quercus,15 Diospyros u.s.w., die uns aus dieser Zeit bekannt sind. Sie waren daher Omnivoren, worauf auch der Zahnbau der eocenen Säugethiere weist. Erst von der untern Miocen-Zeit an begegnet uns ein grösserer Reichthum von Gramineen u. zahlreiche Bäume u. Sträucher mit fallendem, weichem Laub (so Acer, Ulmus, Carpinus, Corylus, Alnus, Fraxinus Robinia u.s.w.).16 Von dieser Zeit an war daher das Land mit Wiesengründen bedeckt u. mit Baum- u. Strauch-werk bewaldet, das durch seine Blätter zur Ernährung der Säugethiere dienen konnte. In diese Zeit fällt nun aber gerade eine grosse Umwandlung in der Säugethierwelt, indem die Wiederkauer zu den dominirenden Waldthieren werden u. die Omnivoren mehr zurücktreten. Es hat Kowalevsky gewiss mit vollem Recht in seiner interessanten Monographie der Anthracotherien auf diese Erscheinung hingewiesen, nur hat er auf die Gramineen einen zu grossen Werth gelegt, indem er ihnen allein eine solche Bedeutung zuschreibt.17 Es leben die Wiederkäuer keineswegs nur von Gramineen, ja wir sehen, dass manche nahe verwandte Arten in dieser Beziehung grosse Verschiedenheit zeigen (so Schaaf u. Ziege) u. viele leben mehr vom Laub der Bäume u. Sträucher als vom Gras.

Durch den Tod Lyells ist mir eine grosse Freude zu nichte geworden.18 Ich habe ihm das Buch per Post zugesandt, es hat ihn aber nicht mehr bei Bewustsein getroffen. Ich habe an ihm einen lieben, vortrefflichen Freund verloren, dessen ich stets in herzlichster Dankbarkeit u. Liebe gedenken werde!

Noch habe ich eine grosse, vielleicht unbescheidene Bitte an Sie. Es wäre mir eine grosse Freude Ihre Photographie zu besitzen u. möchte Sie um dieselbe bitten.

Mich Ihnen bestens empfehlend | verbleibe | in grösster Hochachtung | Ihr ergebenster | Oswald Heer.

Zürich | 1 März 1875.

Es macht mir zwar keine Mühe das Englische zu verstehen, wohl aber es zu schreiben, daher ich so frei bin Ihnen einen deutschen Brief zu senden.

[Contemporary translation]

Your friendly lines of last year … encourage me to send you the third vollume of my Flora arctic fossils, & to write you a few lines beforehand. I have put the book in a parcell to our common friend Dr. Hooker, & hope it will soon reach you. The same contains a representation of the chalk-Flora of the arctic zone, which has been collected partly in Greenland between 70o & 71 N. partly in Spitzbergen in 71o by Professer Nordanswöld. Happily there was discovered in Greenland an older Chalkflora, which probably belongs to the Urgon at the same time also a younger flora which is to be derived from Cenoman. The first consists almost entirely of Cryptogama, (first Forna) Cycadeen? Coniforen etc & has a sub tropical character. A single speciës of angiospermen Dicotyledonen could be pointed out, a Populus which belongs to a group of Pappela which appears in the upper chalk & in the tertiary in many species, & in the possenphratica has the same living representatives. This is the oldest as yet named dicotyledon plant. Of course with the exception of the gymnopermen, (which are very .... from the real Dicotyledonen. The Dicotyledonen in the lower chalk of Europe are missing, but on the contrary they appear in the upper chalk, & even in the Cenoman far spread in Europe & America & they appear in this part (i.e. upper chalk) in North Greenland, & not in single types but rather in a whole row of Species, which belong to families which vary from each other in system widly as Pappela, Fious, Myrica, Diospyros—Araliaceen, Magnouliaceen, Myrtaceen, Leguminosen; etc. Many of these families we have received not alone the leaves of but also the fruit, as Fious, Myrica, Panax, Magnolia. It may certainly be, that single ones of these species had their beginning already in the lower chalk, , & per haps were discovered. But even if we allow that the Dicotyledonen begin with the lower chalk, we must own that this division of the plant kindgom which forms the chief mass of the vegitation

In the upper chalk a great change however appears all at once in the Flora, and especially where ?hitherto—fossile plants are found in it; in Mähren ?Moravia Bohemia Saxony in the Harz mountains, at Quedlinburg in Westphalia in Greenland, in Nebraska & in tropical Africa (whence I have lately received Diospyros seeds from Dr. Schweinfurth from the upper chalk) appear now for the first time the (angiosperm) Dicotyledons & impart in a relatively short time to the flora an entirely new physiognomy. then In the Eocene we have a further development of these forms. An immensely long time has passed up to the time when the first Dicotyledons arose, and when these were formed, a rapid development of them took place. Only one other important appearance stands in relation therewith. Setting on one side the little mammals of the Jura, which probably lived on insects, the omnivorous & herbivorous mammals first appear in the Eocene. We may well say that in all earlier periods, from the coal up to the middle chalk, plants afforded no sustenance to mammals. No mammals live on fern, Equisetaceæ & Lycopods, and further the Aseadeæ (or Cycadeæ) & Conifers afford a very scanty nourishment, which at the present time is only used slightly in necessity & famine. Dycotyledons & Gramineæ afford the chief vegetable food.

The Gramineae now appear too one by one, with the dicotyledons. Simultaneously in the chalk the conditions of life for them arise; yet they must have already have had a certain dissemination so as to be able to serve as a basis for their existence. Then in the under Eocene paridigitata & imparidigitata arise; & even altho’ isolated types had appeared in their upper chalk, yet the mammals in the Eocene show us the same appearances, as the plants in the upper chalk, since amongst them also a strikingly rapid development took place during this period. Just as in the upper chalk period, so also in the Eocene    In Europe the flora consisted for the most part of trees & shrubs with stiff leathery leaves, and meadows formed of grasses were wanting, as also was wanting bushes with soft leaves.

The mammals were supported principally from roots of plants & on fruits seeds of trees, fruits of the Ficus, the Cluerous (??) the Diospyros &c, which are known to us as belonging to this period. That they were omnivorous on all these fruits, the teeth structure of the Miocene Mammals proves to us.

From the lower Miocene period onwards a greater wealth of Gramineæ meets us, and numerous trees & shrubs, with falling soft leaves (as Acer Ulmus Carpinus Corylus, Alnus Fraxinus Robinia (?) &c)

From this time on, the country was covered with meadows which were wooded with trees & shrubs, which might serve by their leaves to nourish mammals. At this period a great change appears in mammal fauna, whilst the chewers of cud become the dominating forest animals, and the omnivorous retire more & more into the background

Kovalevsky has certainly in his interesting monograph correctly established (???) the Anthracothercia on this appearance, only he has built a too great a structure on the Gramineæ, because he ascribes to them alone so great a significance. The chewers of cud live by no means entirely on Graminea; observe indeed, that many nearly allied Species exhibit great differences in this respect (for example sheep & goats) and many live more on leaves of trees & twigs than on grass.

Lyell’s death has destroyed a great pleasure for me   I sent him the book by post, but it did not reach him alive. I have lost in him a dear excellent friend, whom I shall always think of in the most heartfelt thankfulness & love.

I have yet a great, perhaps forward (immodest) request to make you. It would be a great pleasure for me to possess your photograph, & might I request it | O. Heer.

CD annotations19

End of contemporary translation: ‘Lyell— last time I saw him he was talking with The greatest interest about you & when he last saw you’ pencil; ‘Photograph’ brown crayon; ‘(Yourself)’ pencil; ‘My new Book— | It is most wonderful case— on whatever view of evolution is taken I shd be inclined to speculate on that head   plants, having been developed in an isolated area then spread’ pencil; ‘Many as have been the wonderful discussions in Geology during last years none have exceeded or equalling yours about the N. Flora— | Your Book’ ink

Footnotes

For a translation of this letter, see Appendix I. A contemporary translation of the letter, with annotations by CD, is included above.
Heer sent the third volume of his seven-volume work on fossil flora of the Arctic regions (Heer 1868–83). CD’s copies of volumes 3–6 are in the Darwin Library–CUL. His copy of the first part of the second volume is in the Darwin Pamphlet Collection–CUL.
Urgonian refers to a series of massive limestones of the Lower Cretaceous system as developed at Orgon in the Durance valley, France; Cenomanian refers to a subdivision of the Upper Cretaceous period, corresponding to the Lower Chalk and Upper Greensand of British geologists (OED). Cryptogamia was a Linnaean order that included all plants with concealed reproductive organs. Although the name is no longer a valid taxon, the descriptive term cryptogam is still used to refer to plants that reproduce by spores.
Dicotyledoneae is a former class of flowering seed-plants or angiosperms characterised by the presence of two embryonic seed-leaves or cotyledons; it is now subsumed within the class Magnoliopsida. Populus euphratica, the Euphrates poplar, belongs to the family Salicaceae.
Gymnosperms (infradivision Gymnospermae), or non-flowering seed-plants, may have anywhere from two to twenty-four embryonic leaves or cotyledons, and the number may vary within some species.
Ficus is the genus of figs; Myrica is the genus of bayberry; Diospyros is the genus of persimmons. Araliaceae is the family of ginseng and ivy; Magnoliaceae is the family of magnolias; Leguminosae (the alternative name Fabaceae is now often used) is the family of peas and legumes.
Panax is the genus of ginseng.
The time interval separating the end of the Devonian period from the beginning of the Cretaceous period had not been determined. Charles Lyell had attempted to quantify the length of geological periods in the tenth edition of his Principles of geology (C. Lyell 1867–8, 1: 300–1), but had removed the estimates from later editions (see Burchfield 1998 for more on estimates of geological time during this period). Monocotyledoneae is a former class of flowering seed-plants or angiosperms characterised by the presence of one embryonic seed-leaf or cotyledon; it is now subsumed within the class Magnoliopsida. The present superorder Lilianae includes all the monocots.
Georg August Schweinfurth.
Equisetaceae is the family of horsetails; Lycopodiaceae is the family of club mosses; Cycadaceae is the family of cycads; Coniferae was formerly the class of conifers (now Pinopsida).
Gramineae (the alternative name Poaceae is now often used) is the family of grasses.
Paridigitata and Imparidigitata were former subdivisions of herbivores roughly equivalent to the modern orders Artiodactyla and Perissodactyla (even-toed and odd-toed ungulates).
Quercus is the genus of oaks.
Acer is the genus of maples; Ulmus: elms; Carpinus: hornbeams; Corylus: hazels; Alnus: alders; Fraxinus: ashes; Robinia: locust trees.
In his monograph on Anthracotherium (a genus of ungulates that became extinct by the late Miocene period), Vladimir Onufrievich Kovalevsky had discussed changes in dentition in ungulates from the Miocene to the present day, arguing that the principal cause for the changes was the shift to a graminivorous diet (Kovalevsky 1873–4, pp. 272–3). He concluded that most ungulates that could not shift from an omnivorous to a graminivorous diet had gradually died out (ibid., p. 274).
Charles Lyell died on 22 February 1875 (ODNB).
CD’s annotations are notes for his reply to Heer of 8 March [1875].

Bibliography

Burchfield, Joe D. 1998. The age of the Earth and the invention of geological time. Geological Society, London, Special Publications 143: 137–43.

Heer, Oswald. 1868–83. Flora fossilis arctica. Die fossile flora der Polarländer. 7 vols. Zurich: J. Wurster & Comp.

Kovalevsky, Vladimir Onufrievich. 1873–4. Monographie der Gattung Anthracotherium Cuv. und Versuch einer natürlichen Classification der fossilen Hufthiere. Palaeontographica. Beiträge zur Naturgeschichte der Vorwelt 22 (1873–6): 131–347.

Lyell, Charles. 1867–8. Principles of geology or the modern changes of the earth and its inhabitants considered as illustrative of geology. 10th edition. 2 vols. London: John Murray.

ODNB: Oxford dictionary of national biography: from the earliest times to the year 2000. (Revised edition.) Edited by H. C. G. Matthew and Brian Harrison. 60 vols. and index. Oxford: Oxford University Press. 2004.

OED: The Oxford English dictionary. Being a corrected re-issue with an introduction, supplement and bibliography of a new English dictionary. Edited by James A. H. Murray, et al. 12 vols. and supplement. Oxford: Clarendon Press. 1970. A supplement to the Oxford English dictionary. 4 vols. Edited by R. W. Burchfield. Oxford: Clarendon Press. 1972–86. The Oxford English dictionary. 2d edition. 20 vols. Prepared by J. A. Simpson and E. S. C. Weiner. Oxford: Clarendon Press. 1989. Oxford English dictionary additional series. 3 vols. Edited by John Simpson et al. Oxford: Clarendon Press. 1993–7.

Translation

From Oswald Heer1   1 March 1875

My most honoured Sir!

Your friendly lines of last year, for which I send my best though belated thanks, encourage me to send you the third volume of my Flora fossilis arctica, and to preface it with a few lines.2 I have added the book to a parcel addressed to our mutual friend, Dr. Hooker,3 and I hope that it will reach you in the near future. The same contains an account of the Cretaceous flora of the Arctic zone, some of which was collected by Prof. Nordenskiöld4 in Greenland between 70 and 71o N. lat., and some in Spitzbergen up to 78o N. Fortunately, an older Cretaceous flora, which probably falls into the Urgonian, and also a younger Cretaceous flora of the Cenomanian, have both been discovered. The former consists almost exclusively of Cryptogamia (chiefly ferns), cycads and conifers, and is subtropical in character.5 Of angiospermous Dicotyledoneae only a single species could be detected, a Populus that belongs to a group of poplars represented in the Upper Cretaceous and the Tertiary by a number of species, whose closest modern representative is Pop. euphratica.6 This is the oldest known dicotyledonous plant yet (naturally with the exception of gymnosperms, which are very different from the true Dicotyledoneae).7 In Europe, the Dicotyledoneae of the Lower Cretaceous are also missing; however, they appear widely distributed in the Upper Cretaceous, and in fact already appear in the Cenomanian, both in Europe and in America, and in the same way they appear at this time in north Greenland too, and not just in a few isolated sorts, but in a whole series of species belonging to families that are far apart in the system, such as poplars, Ficus, Myrica, Diospyros,— Araliaceae, Magnoliaceae, Myrtaceae, Leguminosae and more besides.8 Not only the leaves, but also the fruit of a number of these families are preserved, as of Ficus, Myrica, Panax,9 Magnolia.— Admittedly it is possible that some of these kinds originated in the Lower Cretaceous and may yet be discovered there. However, if we allow that the Dicotyledoneae begin with the Lower Cretaceous, we must still concede that this section of the vegetable kingdom, which forms the bulk of present-day vegetation, appears relatively late and that it underwent a substantial transformation within a brief (geologically speaking) period of time. The interval from the Devonian to the Cretaceous is immensely long, and, as far as we know until now, the vegetable kingdom then consisted only of cryptogams, conifers & cycads and a few monocots.10 In the Upper Cretaceous, however, the flora suddenly underwent a great transformation, and wherever up to now fossilised plants of this period have been found: in Moravia, Bohemia, Saxony, in the Harz Mountains, near Quedlinburg, in Westphalia, near Aachen, in the South of France, in Russia, in Greenland, in Nebraska and in tropical Africa (from where I have recently received Diospyros fruit of the Upper Cretaceous, from Dr. Schweinfurth11), there appear for the first time the (angiosperm.) Dicotyledoneae, and within a relatively short period they fundamentally change the face of the vegetable kingdom. In the Eocene these forms develop yet further. It took an immensely long time for the first Dicotyledoneae to arise, and as soon as they appeared, they developed at great speed.

Another important phenomenon seems to me to be linked to this. Apart from the small mammals of the Jurassic period, which probably fed on insects, omnivorous and herbivorous mammals only appear in the Eocene. We can probably say that in all earlier periods, from the Carboniferous to the middle Cretaceous, plants would not have provided sustenance for mammals. No mammal lives on ferns; Equisetaceae and Lycopodiaceae, as well as Cycadaceae & Coniferae,12 supply only very meagre nourishment, which present-day mammals turn to only in an emergency and for instance during a famine. The bulk of the nourishment they get from plants is supplied by the Dicotyledoneae and Gramineae.13 Now, it is true that there were already a few Gramineae together with Dicotyledoneae in the Cretaceous, and hence the living conditions for mammals were already given at this stage, but these plants had to have spread to a certain extent to be able to provide the foundation for their existence. Since Paridigitata & Imparidigitata14 already occur in the Lower Eocene, a few kinds may already have developed in the Upper Cretaceous, but mammals in the Eocene show us the same picture as plants in the Upper Cretaceous since remarkably rapid development also occurs in them at this time. As in the Upper Cretaceous period, so also during the Eocene in Europe, the plant world was made up largely of trees and shrubs with tough leathery leaves. Still missing were the grasses that form the meadowlands and the soft-leaved scrub. Mammals then must have lived mainly on roots and fruits of Ficus, Quercus,15 Diospyrus, etc., the trees we know from this period. They were omnivores, which is also known by the dental structure of Eocene mammals. Only from the Lower Miocene onwards do we encounter a greater wealth of Gramineae and numerous trees and shrubs with soft, falling leaves (such as Acer, Ulmus, Carpinus, Corylus, Alnus, Fraxinus Robinia etc.).16 From this period on, the earth was covered by meadowlands and it was forested with trees and shrubs, whose leaves served the mammals for their nourishment. Now, it is in this very period that mammals undergo a great change, in that ruminants become the dominant forest animals, and omnivores recede more. Kowalevsky, in his interesting monograph on Anthracotherium, has quite rightly drawn attention to this occurence, only he has put too much emphasis on the Gramineae, attributing to them alone such a significance.17 Ruminants hardly live on Gramineae alone, on the contrary, we see that some closely related kinds differ greatly in this respect (such as sheep and goat), and many of them live more on leaves of trees and bushes than on grass.

Lyell’s death has deprived me of a great joy in my life.18 I sent him the book by mail, but it failed to reach him while he was still conscious. I have lost a dear, excellent friend in him, one I will always think of with the most heartfelt gratitude and love!

I still have a great, perhaps immodest favour to ask. It would be such a joy for me to possess your photograph and I should like to ask you for it.

With my best regards to you | I remain | with the greatest respect | Your most devoted | Oswald Heer.

Zurich | 1 March 1875.

While I have no trouble understanding English, I can’t write in English, so I took the liberty of sending you a letter in German.

Footnotes

For a transcription of this letter in in its original German, and a contemporary translation, see pp. 88–93
Heer sent the third volume of his seven-volume work on fossil flora of the Arctic regions (Heer 1868–83). CD’s copies of volumes 3–6 are in the Darwin Library–CUL. His copy of the first part of the second volume is in the Darwin Pamphlet Collection–CUL.
Urgonian refers to a series of massive limestones of the Lower Cretaceous system as developed at Orgon in the Durance valley, France; Cenomanian refers to a subdivision of the Upper Cretaceous period, corresponding to the Lower Chalk and Upper Greensand of British geologists (OED). Cryptogamia was a Linnaean order that included all plants with concealed reproductive organs. Although the name is no longer a valid taxon, the descriptive term cryptogam is still used to refer to plants that reproduce by spores.
Dicotyledoneae is a former class of flowering seed-plants or angiosperms characterised by the presence of two embryonic seed-leaves or cotyledons; it is now subsumed within the class Magnoliopsida. Populus euphratica, the Euphrates poplar, belongs to the family Salicaceae.
Gymnosperms (infradivision Gymnospermae), or non-flowering seed-plants, may have anywhere from two to twenty-four embryonic leaves or cotyledons, and the number may vary within some species.
Ficus is the genus of figs; Myrica is the genus of bayberry; Diospyros is the genus of persimmons. Araliaceae is the family of ginseng and ivy; Magnoliaceae is the family of magnolias; Leguminosae (the alternative name Fabaceae is now often used) is the family of peas and legumes.
Panax is the genus of ginseng.
The time interval separating the end of the Devonian period from the beginning of the Cretaceous period had not been determined. Charles Lyell had attempted to quantify the length of geological periods in the tenth edition of his Principles of geology (C. Lyell 1867–8, 1: 300–1), but had removed the estimates from later editions (see Burchfield 1998 for more on estimates of geological time during this period). Monocotyledoneae is a former class of flowering seed-plants or angiosperms characterised by the presence of one embryonic seed-leaf or cotyledon; it is now subsumed within the class Magnoliopsida. The present superorder Lilianae includes all the monocots.
Georg August Schweinfurth.
Equisetaceae is the family of horsetails; Lycopodiaceae is the family of club mosses; Cycadaceae is the family of cycads; Coniferae was formerly the class of conifers (now Pinopsida).
Gramineae (the alternative name Poaceae is now often used) is the family of grasses.
Paridigitata and Imparidigitata were former subdivisions of herbivores roughly equivalent to the modern orders Artiodactyla and Perissodactyla (even-toed and odd-toed ungulates).
Quercus is the genus of oaks.
Acer is the genus of maples; Ulmus: elms; Carpinus: hornbeams; Corylus: hazels; Alnus: alders; Fraxinus: ashes; Robinia: locust trees.
In his monograph on Anthracotherium (a genus of ungulates that became extinct by the late Miocene period), Vladimir Onufrievich Kovalevsky had discussed changes in dentition in ungulates from the Miocene to the present day, arguing that the principal cause for the changes was the shift to a graminivorous diet (Kovalevsky 1873–4, pp. 272–3). He concluded that most ungulates that could not shift from an omnivorous to a graminivorous diet had gradually died out (ibid., p. 274).
Charles Lyell died on 22 February 1875 (ODNB).

Bibliography

Burchfield, Joe D. 1998. The age of the Earth and the invention of geological time. Geological Society, London, Special Publications 143: 137–43.

Heer, Oswald. 1868–83. Flora fossilis arctica. Die fossile flora der Polarländer. 7 vols. Zurich: J. Wurster & Comp.

Kovalevsky, Vladimir Onufrievich. 1873–4. Monographie der Gattung Anthracotherium Cuv. und Versuch einer natürlichen Classification der fossilen Hufthiere. Palaeontographica. Beiträge zur Naturgeschichte der Vorwelt 22 (1873–6): 131–347.

Lyell, Charles. 1867–8. Principles of geology or the modern changes of the earth and its inhabitants considered as illustrative of geology. 10th edition. 2 vols. London: John Murray.

ODNB: Oxford dictionary of national biography: from the earliest times to the year 2000. (Revised edition.) Edited by H. C. G. Matthew and Brian Harrison. 60 vols. and index. Oxford: Oxford University Press. 2004.

OED: The Oxford English dictionary. Being a corrected re-issue with an introduction, supplement and bibliography of a new English dictionary. Edited by James A. H. Murray, et al. 12 vols. and supplement. Oxford: Clarendon Press. 1970. A supplement to the Oxford English dictionary. 4 vols. Edited by R. W. Burchfield. Oxford: Clarendon Press. 1972–86. The Oxford English dictionary. 2d edition. 20 vols. Prepared by J. A. Simpson and E. S. C. Weiner. Oxford: Clarendon Press. 1989. Oxford English dictionary additional series. 3 vols. Edited by John Simpson et al. Oxford: Clarendon Press. 1993–7.

Summary

Comments on his Flora fossilis Arctica [vol. 3 (1875)]. Discusses successive appearance of plant families in geological periods. Relates plant development to rise of herbivorous mammals.

Comments on death of Charles Lyell.

Letter details

Letter no.
DCP-LETT-9876
From
Oswald Heer
To
Charles Robert Darwin
Sent from
Zurich
Source of text
DAR 166: 130
Physical description
ALS 6pp (German), trans 11pp †

Please cite as

Darwin Correspondence Project, “Letter no. 9876,” accessed on 28 March 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-9876.xml

Also published in The Correspondence of Charles Darwin, vol. 23

letter