Dear Sir.

About one year ago (7^th Jan^y) you had the kindness to write me a note acknowledging the communication of some Geological papers of mine.¹ Your letter was thankfully received, I assure you; but I did not feel at liberty to answer it and thus to indiscreetely call for a continuance of correspondance, merely for my own pleasure and advantage. Even now, I am not certain that the matters which I wish to discuss in this letter will appear sufficiently interesting to you to compensate any loss of your time.

A System like yours, on the Origin of Species could not but hurt more or less some of the preconceived ideas of many, of these ideas which we might call hereditary ones, resulting of our first impressions, of the first teachings received by motherly care and affection. Conceited ideas perhaps, often unreasonable and unexplained, but most tenacious because they have followed us from the cradle all along the path of our life and have been considered as faithfull missionaries of truth and as reliable guide of our human pilgrimage. I can not explain but in that way the antagonistic repulsion which I felt against your system when I read its exposition for the first time. I considered it then as hostile to every kind of religious faith and religious feelings and it is only with great effort that I could come to examine without decided partiality some of your arguments and your proofs. By and by this mistrust has passed away; I have read your book again and again and now I find that your system not only does not contradict any of the Dogmas of my Christian faith;² but on the contrary that it satisfies my reason far better than any other human explanation could have done, concerning some of the most obscure points of the biblical teachings; the miraculous birth of Christ, a new beying the first species of a higher and Divine type; the doctrine of grace &c: It is not for discussing these matters that I take the liberty of writing to you. But I mention my own impressions as an explanation of what many others have experienced like me and perhaps also as an excuse of a feeble attempt of mine to seek for geological proofs in contradiction of your system.

When your remarkable book came out,³ I was just engaged in a general examination of the fossil Flora of the coal measures of North America and could not but try to test the value of some of your systematic conclusions in applying them to what I saw of the vegetation of this ancient world.⁴ I can not set aside any of the assertions given as general remarks in Silliman’s Journal vol: 30 Nov^b. 1860 p: 378 to 384.⁵ (I mail a copy of the pamphlet, in case you had not the journal). But I now think that the various changes perceptible in the vegetation of the coal at different horizons and also the want of analogy between the groups of vegetation of various beds of coal can be explained easily without evidencing any valuable argument against your theory of the origin of species. It is true indeed that the first appearance of land plants in the lowest part of the coal basins do not show anything like what we might consider as an incipient vegetation. Most of the remains found in connection with the most ancient deposits of combustible matter belong to large trees, mostly to species of Lepidodendron, Stigmaria, Calamites et Sigillaria. Great trunks of fossil wood apparently pertaining to some extinct species of conifers, are also found in the black shales of the upper and even of the middle Devonian of North America, while the true coal measures do not have any fossil remains referable to this family of plants. It appears confirmed also from my own observations and from those of other surveyors of our coal fields that the vegetation from which the coal has been derived shows a diminishing power from the base, up to the highest strata of the measures: that the great Lepidodendron are not found higher than what we call here the low coal measures (coal N^o 4); that above this, the Lepidodendron are succeeded by much smaller species of a different order; by Ferns, Sphenophylleæ, Asterophylliteæ, Calamitaceæ &c. But it is right also to remark; that we do not know yet where are the lowest limits of land or terrestrial vegetation. They were no long time ago removed from the base of the coal measures to the middle of the Devonian; now they are put down as far as the upper Silurian. Further discoveries may still remove them lower. Hence it is clear that we do not know yet what kind of plants covered the earth at first after it emerged from the sea   And concerning the other peculiar features of the vegetation of the coal, as much as we can know them from rare and imperfect fossil remains, they may be easily explained by the same influences which have caused peculiar or apparently anormal features in the formation of our actual peat-bogs. For, the more I become acquainted with the coal formations, the more I am persuaded that the peat-bogs of our time, as well for their formation and general growth as for the peculiarity of their vegetation, are microcosmical representatives of the great peat bogs of the coal epoch. Now, in the peat bogs of Europe, one can observe successive changes of vegetation which at first sight could appear far more opposed to a law of transformation of species like yours, than those which have been remarked in the coal measures. In the bogs of Les Verrières a valley of the high Jura of Swizerland, about 2000 feet higher than the lake of Neuchatel, one finds at the bottom of the peat formation large trunks of oak trees still perfectly well preserved while the zone of the oak begins now at least 1500 feet lower. This valley of Les Verrieres is thus not only entirely barren of oaks, but no fruit trees, not even cherry trees can live there.⁶

In an inferior valley connected with the former, the val de Travers, about one thousand feet lower, there are still two or three oak trees growing in an orchard   Here the fruit trees of the hardiest kind prosper, but one has to descend still 500 feet lower toward the lake shores to find the actual region of the oak. Thus at the mentioned place, the lowest part of a bank of peat has a deposit of large trees of true dycotiledonous species generally now inhabiting a warmer zone and its upper part is only a compound of mosses Carices, Ericaceæ and small trees of the Conifer family (Pinus pumilio Ches: growing now on its surface)

Observations like this could be repeated in a contrary way and on a larger scale in some of the peat bogs of Danemark and Northern Europa where deep basins or lakes have been by and by filled with successive vegetable deposits grown on their surface and sunk by their own weight. In some of these one finds, at the bottom, on four feet or more of decomposed black hard peat, an overthrown forest of pines; above this, another bed of peat four to six feet thick overlaid by a deposit of white Birch trees; then in ascending six feet of soft peat mostly a compound of Sphagnum and above it another bed of black earthy decomposed peat in which are imbedded enormous trunks of prostrated oaks, three to four feet in diameter so well preserved that they are generally exhumed by the inhabitants and cut for timber. This last deposit is still overlaid by six feet or more of recent peat covered by a forest of beech trees either living and standing or already overthrown and invaded by the sphagnum. Such changes as these, observable in a single formation of our peat bogs are far more remarkable than any of those which have been remarked till now in successive strata of the coal measures—

They are easily explained by external influences, changes of temperature, difference of humidity &c: &c; and have nothing to do whatever with some law of transformation or variation of forms passing to new species.

I am now prepared to admit the same conclusions concerning the successive changes apparent in the vegetation of the coal measures and perhaps also of the successive stages of the tertiary. Changes which may be extended at the same time on wide surfaces or repeated at interval of time on the same localities. And even, I would go furter and say that some facts gathered in examining the carboniferous and subcarboniferous measures, might be considered rather in confirmation than in contradiction of your system.—

Around the Eastern borders of the great Apalachian coal fields of America and generally immediately underlaying the conglomerate (millstone grit) on the base of the true coal measures, there is extended a wide and thick formation mostly a succession of red shales, the Old Red Sandstone or a representative of it. These shales disappear to the Westward and are replaced by subcarboniferous limestone and sandstone strata, containing at different horizons thin beds of coal with remains of Lepidodendron, Sigillaria, Calamites, Knorria, all species of the true coal formation. Now, these red shales of a contemporaneous formation bear evidence of a constant alluvial action. They are every where marked by ripples caused by the movement of shallow water, apparently the tides; they bear the prints of drops of rain, of feet or of tracks of small crustaceæ and larger batracians and their flora is of a character totally different from that of the coal measures. If the Pennsylvania Geological report of Prof H. D. Rogers is attainable to you, you may see in it plate 22 and 23 the figures of some peculiar leaves belonging to this formation.⁷ Some others are represented and described in my own report of the same work,⁸ plate 1 fig 10 & 11 & pl. 3 fig 1 to 1d, as Noeggerathiæ species— I have had a good opportunity to study in place the plant figured pl: 23 and seen many fine, nearly entire specimens of it. The plants were born on a rhizoma from three to six feet long, two to three inches in diameter dividing at its base in a wide net of small round, very long rootlets. The leaves forming a large crown or umbell were from three to four feet in length,, six inches broad in the middle, dichotomously dividing toward their extremity and all the divisions were covered with distichous round, attenuated leaflets unordinately placed and becoming shorter in ascending. I have even found attached to its rhizoma an undeveloped head of leaves of a round- oval form, resembling the head of a cabage. In breaking it, the leaves were seen folded and closely pressed upon another, just like leaves of dicotyledonous plants in their vernation. These and other characters led me to conclude that this plant is not quite an Algoid but that it rather belongs to a peculiar order, showing in its ramification, in the form of its leaves, of its long round rootlets some analogy with the family of the Lepidodendreæ while it has at the same time especially by the position and irregular form of the leaflets some characters of the Fucaceæ. These plants were evidently adapted to their station. Their long rhizoma or main root, their large crown of long leaves floating on the low water or extended on the soft mud show a perfect harmony of forms with their habitat and would indicate a kind of transition from marine to terrestrial vegetation. In any case they conclusively prove that the vegetation of the coal measure was like that of our peat bogs of a peculiar character and that there were at the same epoch groups of vegetables of quite other and distinct types. The leaves of plate 22. appear to belong also to a peculiar family of plants intermediate perhaps between Fucaceæ and Ferns. They are somewhat related by their form to Species of the genus Schizopteris of the coal measures. As for the Noeggerathiæ, the most common plants of the Red Sandstone, they are not true Ferns, indeed; but what are they? Prof. Brongniart places them between the Cicadeæ and the Conifers;⁹ some species have indeed the appearance of small Cicadeæ; but some others like Noeggerathia Bockschiana Lsqx. are by the disposition of their leaflets and their nervation much like species of Sphenopteris? These would also indicate transient forms.

In Silliman’s Journal vol: 3 Nov^b. 1863 p. 378,¹⁰ I have remarked that in connection with a bed of coal of the higher measures (Coal N^o 12) there had been found a species related by its form to some fossil ferns of the Oolite series. “It is the remarkable Neuropteris Moorii Lsqx, which by its pointed leaves and alate primary or secondary rachis is distinct from any typical form of the coal ferns. It may be compared by its general appearence to Alethopteris Whitbiensis Brgt. of the Oolite of England”. Since the above was written, I have found a curiously coinciding remark in a new work (Le terrain du Transition des Vosges) of my friend the celebrated Bryologist W. P. Schimper of Strasbourg.¹¹ He says; page 320: that some of the detached coal banks of the Northern part of the Black-Forest, though evidently of contemporaneous formation with the great coal basin of Sarrebourg and belonging to its higher strata contain already some species considered as characteristical of the Trias; viz a Pterophyllum somewhat analogous to Pterophyllum Sægeri.

The flora of the highest strata of the Upper coal measures of N. America is still nearly unknown, as are also the different floras of all the formations intermediate between the Cretaceous or even the Tertiary and these coal measures. Hence we know nothing concerning the transitional or relative vegetable forms between those far distant epochs. But relations, especially and some differences also are evident enough between the plants of our tertiary and those of our actual flora. You have kindly alluded in your letter¹² to a paper of mine, on some tertiary plants of Vancouver Island of Tennesee &c:¹³ Since this paper was written, I have had opportunity to examine a large number of specimens of Tertiary fossil leaves, mostly collected in the state of Mississipi, from strata apparently contemporaneous with those from which the plants of Tennesee had been obtained. Nevertheless, these leaves show still more analogy perhaps than the former ones, with species of our time and of our N. American flora. There is a Quercus, scarcely separable from Quercus Castanea var: Montana; a Cornus, exactly like Cornus Sericea; a Rhamnus with apparently recurved margins, looking as if the lowest pair of nerves were running all around the leaves and forming border; just the same appearance as in Rhamnus Carolinianus. You may see a figure of this species in my report on the Arkansas survey under the name of Rhamnus Marginatus.¹⁴ There are also some species of Carya; one like C: alba; the seed of a Pappaw; a Prunus resembling P: serotina; a Populus, a Salix and three or four species of Magnolia &c: &c: A lower formation which the State Geologist of Mississipi supposed to belong to the upper Cretaceous,¹⁵ but which I consider as lower tertiary has furnished an aboundance of leaves of a Sabal (Sabal major? Heer) of a Calamopsis, two Salix one Cinnamomum, one Prunus. &c:— Though the identity of species of the tertiary with some of our epoch is denied, probably with right, the generic and even specific relations are evident and numerous enough. And as a natural consequence the general character of the flora of both epoch is very similar. Indeed the forms which we might call geological ones are far more remarkably preserved here than in Europe   And what is still more frappant, we recognize already in the vegetation of the tertiary some of those characteristic differences which now mark or divide the two longitudinal zones of the Pacific and of the Atlantic slopes. Thus, the tertiary (perhaps Cretaceous?) of California has a species of Sequoia apparently identical (we have a branch only) with Sequoia viridis the predominant arborescent vegetable of that country and those multiform leaves of Quercus Gaudini Lsqx closely related if not identical with Quercus densiflora, another of the most common trees of California. In the tertiary of the Mississipi Valley, per contra, the flora is marked by Oaks of of a different type, at least for the form of the leaves, by Magnolia, and other species related to our present Eastern vegetation. From the little we know of the fossil flora of California, it appears that the vegetation of the tertiary of Europe has a far greater relation with it than with that of our Eastern Slope.

Have you perhaps received a few months ago a paper on the Californian mosses.¹⁶ I took the liberty of mailing a copy to your adress. The examination of the species of lower or rather of littoral California gave opportunity to some peculiar remarks which may be somewhat in your line of researches. 1^st. The grouping of species of mosses, according to relation of forms is far more striking in this peculiar and so to say isolated flora than I have ever seen it elsewhere; remarkable as well for the total absence of certain groups as for the predominance of others. In the Acrocarpi, for example, the Dicranaceæ are represented by one single species, the most common Dicranum varium. The Trichostomeæ, Grimmiæ and Orthotrochaceæ on the contrary have one half of all the species of mosses of the littoral of California. And among these there are certain groups like that of the Barbulæ which we could call vineales whose forms or species are so numerous and so nearly related that it appears more rational to consider them as mere local varieties resulting of loccal and appreciable influences than as true species. In the Pleurocarpi, the disposition to grouping is still more remarkable. There are no Crypheæ, no Leptodonteæ no Leskeaceæ, no Cylindrothecieæ while there is two Nekeræ much alike, also two Antitrocheæ two or three (according to authors) species of Pterogonium three Alsiæ and in the great division of the Hypna all the species are united in the subgenera: Isothecium Camptothecium Scleropodium, Eurynchium¹⁷ with the exception only of one Shuidium, one Thamnium one Brachythecium and the two universal Amblystegium repens¹⁸ & A. riparium. And what is true of the species of Barbulæ is true also of the species of these groups of Pleurocarpi. The characters which separate these species are so uncertain, apparently so undecided that the observator is constantly in doubt and hesitating between a multiplication of species or the admission of a single species with numerous varieties. In the sub. genus Isothecium for example, I have admitted three species, M^r Mitten¹⁹ has separated into species three other forms and at least two others should be added to the number with the same right to specific distinction. I am certain that Muller who has united Isothecium myosuroides Br Em. & I: stoloniferum Hook. would consider all those species as varieties of the first named and perhaps that would be right.²⁰

2^d The disposition to vary is extremely remarkable in the Californian mosses, even on different part of the same specimens. And this disposition does not affect only the organs most generally variable, like the leaves, the stems, the ramification but also those which are generally considered as persistant in their forms and consequently as the most important for classification. To quote only a single case: Bartramia Menziezii of Hooker²¹ has its capsule either without any trace of a peristomal membrane or with the mouth surrounded with a membran either entire or irregularly laciniate or with a simple but perfect peristome of articulated teeth. So remarkable are these differences which are nevertheless sometimes observed on a same specimen that M^r Hampe has separated the gymnostom form and made of it a new Species of Glyphocarpa.²² Thus, differences observable on a single specimen have made of the same moss two genera and two species also. Variations of the same kind might be mentioned for a number of cases similar to this peculiar one.

But this letter is already too long and I must hasten to close it. Allow me only to take the liberty of making some inquiries concerning a point of interest for my researches on the formation of the peat bogs. More than twenty years ago, I read in the account of your travels in the Southern hemisphere an assertion which I quoted in a book on the peat bogs (Neuchatel 1844).²³ It is: that in the peat bogs of South America contrary to what happens in Europe, no species of mosses enters into the composition and formation of the peat: that Astelia pumile Br.²⁴ & Donatia Magellanica cover nearly entirely the peat bogs of Terra del Fuego and that both these plants are the essential constituents and agents in the formation of the peat &c. I quote from memory. Your book is not accessible to me now. As I consider that a constant and aboundant humidity is of necessity for the formation of the peat; as even in the great peat bogs or swamps of our Southern states where the vegetation of the canes, of some species of creeping plants &c: is so thick that it forms an impassable barrier, the Sphagnum is the constant agent for concentrating the humidity and covering with it all the woody detritus falling on the surface of the swamps, I would like to know how you explain the slow combustion of the wood and its transformation into carbon under the influence of water, with those Southern plants. Do they absorb the humidity as the sphagnum does. Or is the atmospheric humidity so great that the oxigenation of the woody tissue is stopped by its action. Moreover I have received many specimens of sphagnum of Terra del Fuego with the label: aboundant. Please excuse these questions perhaps undiscreet and do not answer them, if it gives the slightest trouble to do so²⁵

Most respectfully and sincerely your’s | Leo Lesquereux