GEOLOGY. 339 



The question concerning the existence or non-existence of dry land covered 

 with a peculiar vegetation at the epoch of the coal formation, cannot be 

 answered positively or negatively by sufficient evidence. The only fact that 

 would indicate that the marshes of the carboniferous epoch were surrounded 

 by land-bearing plants of different kjnds than those living on the bogs is the 

 presence in coal and in sandstone underlying it of a great number of fruits 

 of different species which by their nature have no relation to any of the 

 other remains preserved in the coal. They have been generally referred to 

 species of Cordaites. But the two only species of our coal measures are 

 found in abundance at geological horizons where the fruits are entirely 

 absent. And even coal shales appearing entirely composed of heaped 

 remains of leaves of Cordaites borassifolia do not contain any fruit. The 

 species of fruit, Carpolithes Corded Gein., referred by M. Geinitz to Cordaites 

 borassifolia, our most common and omnipresent species, has not been found 

 in the coal measures of America. Therefore, either the fruits of unknown 

 relation belong to vegetable species which have grown on the marshes, and 

 of which the remains, leaves and stems, have been entirely obliterated, or 

 those fruits belong to species growing out of the marshes, around them, 

 and have been floated, and thus disseminated in the shales and in the sand- 

 stones. This last opinion appears at first confirmed by a similar process of 

 distribution of species in our deep swamps ; as the hollow trunks of the bald 

 cypress which grows in Drummond lake (Dismal Swamp of Virginia) are 

 filled by fruits, acorns, nuts, etc., of trees which grow on the dry land near 

 its borders. But it is not presumable that species of fruits only could have 

 been floated and disseminated by the agency of water, without any of the 

 branches and of the leaves of the plants to which they belong. And 

 nowhere have the shales, covering what is called the tail of a coal bank, 

 viz. the part abutting against a hill of sand or losing itself in sandstone, 

 exposed any remains of plants of another type than those belonging to the 

 true coal formation. Even where the shales of the coal are covered with 

 remains of shells and of fishes, and consequently formed when the marshes 

 were immersed, all the floated remains of plants which are found with those 

 of animals belong to the common species of the coal. I believe, then, that 

 the plants preserved in the shales of the coal give us a fair representation of 

 the general flora of the carboniferous epoch, as true and as general at least 

 as the fossil plants of the Miocene represent the general flora of the tertiary 

 period. And I suppose that if there was any dry land around the marshes, 

 the vegetation contained only a few species different from those living on 

 the marshes. But this last opinion is merely hypothetical. Leo Lesquereux, 

 Silliman's Journal, Nov. 1860. 



CORRESPONDENCES OF THE AMERICAN AND EUROPEAN COAL- 

 FLORA. 



Considering its generic distribution, the American coal-flora is nearly 

 related to the European. We have only two or three peculiar genera, repre- 

 senting distinct types, which have not been seen in Europe. On the con- 

 trary, Europe has no true and generic types of coal-plants which are not 

 represented in the coal-fields of the United States. 



Considering its species, a more marked difference in the coal-flora of both 

 continents becomes evident. Some of our species represent marked and 

 peculiar forms or types, which are not seen in Europe, though a much 



