192 PAPERS RELATING TO NATURAL HISTORY. 



for hundreds of feet in thickness, with fossilized forms of Hydrophytes. These 

 eyidences of a primordial vegetable world are far more numerous than the 

 remains of land plants in the shales of the Coal Measures. Nevertheless, they 

 appear to belong to plants of a soft tissue, mere cellular, probably mostly 

 unicellular vegetables, the debris of which had not by much the same chances of 

 fossilization. 



" The superabundance of vegetation testified by fossil remains in Palseozoic 

 ages is in accordance with one of nature's most evident laws. The amount of 

 carbonic acid gas is acknowledged to have been, at the Palaeozoic times, far 

 greater in the atmosphere, and also in the water of the seas, than it is now. 

 The prodigious luxuriance of the vegetation of the coal period is rightly ascribed 

 to this fact. It cannot be supposed that in the sea the vegetation, which is 

 there also the intermediate agent between animal life and unorganized bodies^ 

 gaseous or mineral, should have been in a diminutive state when its action was 

 the most in demand, like its development, for the purification of the water and 

 the transformation of the superfluous carbonic acid gas into organism and 

 oxygen. 



" We have no proofs from fossil remains that the Hydrophytes of old attained 

 a very large size. The largest circular fronds of Fucoides Cauda-galli show a 

 diameter of about one foot; the greatest length of the branching Fucoides in 

 the Chemung is from two to three feet. But we cannot judge all the vegetable 

 representatives of an epoch from a few fossilized specimens. These may have 

 belonged to a species of a more compact organization, or to some kind of Cor- 

 allines, which had their surface covered with a hard crust of lime, while other 

 groups of a soft, mere cellular tissue, which had representatives of large size, 

 have been totally decomposed and destroyed. There is no need however of 

 this hypothesis, on the size of the Palseozoic Algae, to argue by comparison on 

 the fecundity of the marine vegetation of old. Small species of Hydrophytes,. 

 in our time, afford sufficient analogies. The great bank of Sargassum, which 

 extends between the 20th and 45th parallel of latitude, covers, according to 

 Humboldt's computation, a space of more than 260,000 square miles. In places 

 this floating bank is so thick as to arrest the progress of vessels, and it appears 

 at present to be of the same extent and to occupy the same place as when it 

 was first noticed by navigators. What can we then infer to have been the 

 result of a vegetation whose force was at least double of what it is now, and 

 which has written its history in whole strata of great thickness ? 



^^ Analogy of Life and Functions in both the Terrestrial and the Maririe Vegeta- 

 ble World. — It cannot be presumed that this whole vegetable world of Palaeozofc 

 seas has left nothing after it but useless petrified remains. In the march and 

 development of nature's productions, nothing of the materials employed is ever 

 lost. The smallest atom of matter is preserved in some way, if not constantly 

 remodelled. Thus we find the key of a new life, of a new creation, in the 

 remains of a destroyed one. Thus, some leaves, preserved by fossilization, in 

 the shales of the Coal Measures, open to our view not only the whole world of' 

 an ancient vegetation, but its predestinated result, coal deposits, slowly laid up 

 by its agency. Thus also the remains of marine plants, in the shales of the 



