in the Mediterranean . 63 



V. Have the Physical Phenomena of the Ancient World any 

 Analogy with the Phenomena now taking place ? 



The preceding facts prove that the petrifaction of shells is not a 

 phenomenon peculiar to past ages, since it is still observed in our 

 own days. This phenomenon cannot, therefore, be brought forward 

 awainst the opinion of the actual permanence of the causes which 

 have operated in the geological epochs. But it may be asked, whether 

 this fact be unique, and whether the other phenomena of the mate- 

 rial world concur with it in inducing us to admit that there is no 

 change in the operating causes, unless it be that they exercise their 

 action with less intensity, and in a less general manner. It forms 

 no part of our intention to discuss this question, — one of the most de- 

 licate and important connected with geology, in all its details, — in this 

 place. We shall confine ourselves to examine briefly whether other 

 facts do not strengthen that one we have been studying, and, like it, 

 prove that the same effects have been always produced on the surface 

 of the globe. 



If we turn our attention to peat-mosses, the most abundant de- 

 posites of carbon we now possess, they will give us, in their alternate 

 beds of marl and sand, a very accurate idea of the conversion of ancient 

 forests into coal. Besides, immense rafts of wood, which the great 

 rivers of America bring down to their mouths, are often transformed, 

 wdien subjected to great pressure, into a carboniferous matter analo- 

 gous to coal itself. Lastly, when wood is found in suitable circum- 

 stances, such as an elevated temperature, or a considerable pressure, it 

 is converted into lignite, very nearly in the same manner as trees were 

 under the same conditions, in geological times. There are no longer 

 formed, it is true, deposites of ferrate of iron similar to those wrought 

 in Sweden ; but ferruginous deposites have by no means ceased to be 

 produced, for they are daily forming in lakes and marshes. These 

 consist principally of limonite (hydrate and peroxide of iron), which 

 is found sometimes in suspension in marshy or lacustrine watei'S, some- 

 times disseminated through sandy formations. To the examples of 

 this previously known, M. Daubree has recently added another, which 

 he has described to the Geological Society of France (184:6.) This 

 fact is not less remarkable than those which had formeidy been noticed. 

 On the other hand, the mmierous stony beaches filled with marine 

 shells, forming every day in so many different places, represent, in 

 the whole of their characters and texture, the coarse limestone or 

 calcaire mocllon, both so replete with the remains of molluscs ; they 

 are both solid and hard. Among the deposites produced every day 

 under our own observation, we may mention those of the Straits of 

 Messina, the harbour of Copenhagen, coasts of Ceylon, the Bay of 

 Sea Dogs, of New Holland, and Guadaloupe. The Antilles also 

 afford many examples of these modern formations. It is tiie same 

 with those of the Island Anastasius {^Santo Anastasio), near the east 

 coast of Florida, opposite the Port of St Augustin. The solid marine 



