Pucbides in the Transition Rocks of North America. 27 



time the herbage of the wheat has been infested with its para- 

 sitic fungus, the Puccinia Graminis ; a coincidence which, it is 

 presumed, ought rather to be interpreted as pointing to certain 

 foregone conditions of the atmosphere or soil, which promoted 

 the growth and multiplication of the respective funguses con- 

 temporaneously, each in its own appropriate soil, the leaves or 

 herbage of the kind of plant in and on which it flourishes. 

 That the fungus of the leaves of berberry can grow on the 

 herbage of wheat, or the fungus of the herbage of wheat on 

 the leaves of berberry, is an idea which the concUisions of 

 science wholly repudiate. The first origin of the funguses, 

 and their appointed agency, must be deemed identical, in time 

 and source, with those of the largest of plants. — J. Z). 



Art. VIII. A Description of a Fossil Vegetable of the Family Fu- 

 coides in the 2\ansition Rocks of North America^ and some 

 Considerations in Geology connected with it. By R. C. Taylor, 

 Esq. 



The accompanying drawing represents an interesting fossil 

 which abounds in certain parts of the transition series in 

 Pennsylvania. This plant was noticed, for the first time, in 

 1831, under the name of Fucoides alleghaniensis, by Dr. 

 Harlan, in the Journal of the Academy of Natural Sciences 

 of Philadelphia. 



Dr. Harlan's description of this fossil jFWcus is so applicable 

 to the specimen before me, that I shall take the liberty of con- 

 densing his account. " It presents one of the richest spe- 

 cimens of vegetable organic remains that have hitherto come 

 under my notice. Not only is the surface of the stone 

 crowded with the forms of this plant, but they lie upon each 

 other three or four layers deep, as is demonstrated by a hori- 

 zontal fracture. They project in bold relief from the surface, 

 with their distal extremities disposed in every direction ; they 

 appear to have been of different ages, and vary in size, 

 accordingly, from 2 in. to 5 in. in length, the largest being 

 eight tenths of an inch in thickness. In breadth they vary 

 from one to five tenths of an inch ; they are generally 

 gently arched from the base towards the apex, and more or 

 less recurved at top ; in every instance the apex is curved 

 downwards, and sinks into the stone. The superior surface 

 of both the stalk and branches is cylindrical, transversely 

 wrinkled by irregular channels, and marked by a longitudinal 

 and depressed line. The digitations or branches are all com- 

 pressed laterally as well as the stalk, and are flisciculated or 



