310 GEOLOGICAL SUEVEY OF THE TEEEITOEIES. 



tiary ejjoch, as it is at our time, merely overgrown by Ferns, Gramens, 

 and CyperacecB, while the borders only had shrubs and trees. It is not, 

 therefore, uncommon to find at the same level and in the same strata at 

 one place remains only of herbaceous species, grasses, rushes, ferns, 

 &c., while at a short distance we have at another locality only petrified 

 arborescent leaves. Therefore the accumulation of fossil remains of the 

 first class at one peculiar place is merely casual, and is of not much 

 account in considering the question of distribution. It may be remarked, 

 also, that at the Tertiary epoch, as at our time, groups of few species 

 grow at the same time over or around the same swami)s ; and that, 

 therefore, we must expect to find the specimens of the same locality 

 representing few species, while on the contrary, at distant localities, 

 equivalent strata have species far different, and which sometimes do 

 not appear to bear relation of age to the others. It is only in the bogs, 

 especially in those from the Ohio Eiver southward, where deposits 

 of peat are generally formed, that there is a diversity of vegetation 

 resembling that which appears in the variety of species found in some 

 localities of our Tertiary strata; as at Evanston, for example, atMarshall, 

 or at the station marked "Six miles above Spring Caiion," &c. In Ala- 

 bama, Virginia, Arkansas, &c., most of these large bogs of our time are 

 overspread by a luxuriant vegetation of trees, shrubs, even reeds and 

 mosses, in a constant and admirable variety. This vegetation bears, in 

 a remarkable manner, the essential characters rei:) resented by the speci- 

 mens of the Tertiary flora from localities remarked above. For example, 

 in the Dismal Swamp, the magnolias are in such abundance that the 

 farmers of the country obtain from them a fair income by the produc- 

 tion of honey. The trees attain around Drummond Lake more than 

 one hundred feet in height. Is not that a remarkable coincidence with 

 the Mississippi Tertiary flora, where on less than twenty species, five 

 represent magnolias with very large leaves'? In crossing, in Arkansas, 

 one bog of this kind, no more than one mile in width, I counted thirty- 

 six species of trees and shrubs representing Magnolia^ Berchemia, 

 BJiamnus, Oymnocladus, Liquidcmihar, Cornus, Viburnum, Ilex, Gletlira, 

 Azalea, Vaccinium, Sassafras, Benzoin, Juglans, Gary a, Myrica, Betula, 

 Taxodium, &c., with five species of oak. The remains of all these 

 living vegetables if petrified would show a collection of types, if not of 

 species, remarkably similar to what is found now in some of the named 

 localities of the Tertiary formations. 



A comparison of geographical distribution of Tertiary species, under 

 about the same degrees of latitude, is now possible only in a general way, 

 and between Europe and North America. The points of difference and 

 analogy may be seen at a glance on the table, without a tedious repeti- 

 tion of names. I will therefore add only the remarks which may give 

 more light to the subject. 



Some families of plants have at our time a wide range of distribution, 

 the Graminew, for examj^le, the Cyperaceece, the Aonentacew, which, at least 

 in England, have one-half of the species identical with ours. We may 

 then expect to find, in the distribution of genera and species of these 

 orders of plants, a striking analogy between the Tertiary plants of both 

 continents. The table indicates about the same proportion of represent- 

 atives of these families at the Tertiary epoch as there is at our time. 

 Of the poplars, for example, we have twenty fossil species, of which 

 eleven are identical with Tertiary species of Europe. This genus indi- 

 cates, by its fossil representatives, a great predominance of species for 

 our country. Perhaps some forms of ours which have been considered 

 as distinct may be reduced by subsequent observations to mere varie- 



