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with the mountain limestone. Near Magdeburg they are found in 

 grauwacke; and M. Elie de Beaumont has, on the south flank of the 

 Alps, found the same vegetable forms in beds of the age of our lias. 

 Positive and negative rules like these, when kept in subordination 

 to new facts, are of the greatest value ; for they record in a few 

 words the result of many observations. 



When we examine a series of formations which are in contact, 

 we constantly find them passing into each other: and when we 

 place the groups of fossils derived from the successive terms of 

 the series in the order of superposition, their passage is still more 

 striking. I do not mean by this to vindicate the transmutation of 

 species ; because that doctrine is opposed by all the facts of any 

 value in determining such a question. Neither do I assume any 

 positive law of continuity such as may be predicated of a formula 

 in exact science. I only wish to state a fact of general observation. 

 We sometimes, however, find that this order in the works of na- 

 ture is interrupted ; a leaf seems to be torn out from the volume 

 of her history. At the same time all the connecting links, which 

 bind the successive mineral masses to each other, are broken ; and 

 their sepai'ation is marked by contortions and disruptions, by 

 heaps of conglomerate, and by all the other proofs of violent internal 

 commotions. But these internal commotions have not been uni- 

 versal : and when we get beyond their operation, we recover the 

 lost page in the history of the world, as it is told in the succession 

 of animal forms, and every thing is again reduced to harmony and 

 order. I do not intend to deny that there may have been certain 

 great epochs of elevation, of such wide-spreading violence as to 

 affect every living thing on the face of the earth. This is a mere 

 question of fact, and to be resolved solely by observation. I only 

 wish to vindicate a principle which we know from experience to 

 be of very extensive application, and to which I have before alluded 

 in this address. I may therefore again be permitted to enforce it by 

 a specific illustration. 



In many parts of the west of England, the lias is separated from 

 the coal measures only by a few hundred feet of red sandstone 

 and conglomerate not containing the vestige of an ox*ganic fossil. 

 It might be supposed (and such a supposition would not be new) 

 — that the red sandstone and conglomerate were formed during some 

 short period of confusion produced by the dislocation of the older 

 rocks — that after a time the sea again became tranquil — and that 

 the fossils of the lias were called into being, upon the ruins of an 

 older world, by a new fiat of creative power. Nor should I object 

 much to such a hypothesis, if it were only regarded as a mere ex- 

 planation of local phenomena. But the fossils of the coal measures 

 bear no resemblance to the fossils of the lias. There is, therefore, 

 such a break of continuity, that we are forced in imagination to 

 supply many new groups of organic forms before we can bring the 

 order of succession into accordance with the known analogies of na- 

 ture. If we continue our investigations to the north of England, 

 we see the coal measures less disturbed and the dolomitic conglo- 



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