84 SIXTEENTH EEPOKT ON THE CABINET OF NAT. HISTOKT. 



8. OBSERVRTMS UPON THE GENERA UPHANTHNIA AND 



DICTYOPHYTON ; 



WITH NOTICES OF SOME SPECIES FROM THE CHEMUNO GROUP OF NEW-YORK, AND THE 



WAVERLY SANDSTONE OF OHIO. 



The remarkable fossils which have been illustrated and described 

 under the names "Hydnoceras" and " Uphantjenia", would not, 

 from the illustrations given, be supposed to possess very intimate 

 relations; but an examination of several forms, which are clearly 

 referable to the same natural group with the former, has led me to 

 suspect that the Uphantjenia may be included among them. 



We cannot suppose that bodies like the Uphant^nia of Van- 

 uxEM are animal remains ; and the Hydnoceras of Conrad, and 

 allied forms, show no shell or crust or other indication of animal 

 origin. We infer, therefore, from numerous observations, that they 

 may belong to some peculiar marine vegetation. 



These remains are usually casts in sandstone, though sometimes 

 preserving the exterior markings ; whije in many instances they 

 consist of impressions of the exterior preserved in the rock, and 

 though occurring in the same beds with land-plants, never preserve 

 the carbonaceous coating common to the latter. From this fact, and 

 from other circumstances, we are led to infer that they belong to 

 the marine vegetation, and that they are Alg^e of a peculiar form 

 and mode of growth.* 



The original specimen described by Mr. Conrad in the Journal 

 of the Academy of Natural Sciences,! is an inverted -subconical, 

 nodiferous body, with reticulate surface-marking, produced by slen- 

 der, radiating and concentric striae. 



The specimen is from sandstone, in Steuben county ; and several others 

 have been obtained from the same region, none of them more complete than 

 the one first described. I have also seen, in the Museum of the Academy of 

 Natural Sciences of Philadelphia, a fragment four inches or more in dia- 

 meter, the section having a subquadrate form.t 



The original specimen from which the Genus Uphant^nia was described 

 is a flabellate frond, representing nearly a quarter of a circle, but imper- 



• In some specimens from Ohio, which occur among fragments of land-plants, there 

 is sometimes an adhering film of minute fragments of carbonaceous matter; but I 

 regard these as having been derived from broken and drifted laud-plants. 



t Vol. viii, p. 567 - 8, 1842. 



X The form and dimensions are given from recollection after many years. 



