244 



Scientific Geology. 



I have assumed it as a fact, that the sandstone formation under con- 

 sideration was deposited beneath the ocean and subsequently elevated. 

 The proof is quite conclusive. Imperfect as is the account which I 

 have been able to give of the organic remains in this group, it contains 

 enough, I think, to settle this point. To whatever species the Fu- 

 coides that occurs in the lower beds may be referred, we may be sure 

 that it was a marine plant. For, says Adolphe Brongniart, "these 

 plants (the Algae, including the Ulvaceae and Fucoideae) grow 

 almost without exception in salt water ; certain Ulvae only being able 

 to develope themselves in fresh water."* This opinion is still farther 

 confirmed by what that same writer says of the species of Fucoides 

 found in the new red sandstone of Mansfeld, in Germany, including 

 of course the bituminous marlite. "Out of seven species," he says, 

 " five, to all appearance, belong to two genera which best characterise 

 marine vegetation in the torrid zone."f If the reticulated fossil, 

 which I have described, be a real Gorgonia, as I suppose, it furnishes 

 another conclusive proof of the marine origin of this formation : for 

 this animal is exclusively marine. As to the fishes found in the shale 

 of this formation, Brongniart says that "many of them may be referred 

 to genera living commonly in fresh water : but others are generally 

 marine ;" and he infers from the other fossils that occur in the same 

 Tock, that it was deposited in salt water. Concerning the Paloeo- 

 thrissum, the only genus of fishes yet found in our sandstone, as no 

 similar fish is now known to exist on the globe, we cannot say wheth- 

 er it was an inhabitant of fresh or salt water, except that the other 

 remains found in connection with this, so far as we know their na- 

 ture, are marine ; and, therefore, we infer that this fish was so too. 



This conclusion corresponds with those that have been made in 

 other countries, as to the new red sandstone group. Every where it 

 is found, when carefully examined, to have had a marine origin ; 

 though some members of the series do contain fresh water remains, 

 or those of land animals, or vegetables ; and hence they are some- 

 times called fluvio-marine : that is, they were formed in estuaries, or 

 shallow seas, into which the organic products of the land and fresh 

 water were occasionally borne by rivers. But in the new red sand- 

 stone of the Connecticut valley, no fossil has yet been found, which 

 is decidedly of fluviatile, lacustrine, or terrestrial origin. 



* Historic des Vegetaux Fossiles, I. Livraison, p. 37. 

 t Idem, p. 43. 



