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XX. — On the Cretaceous and Tertiary Strata of the Danish Islands of 

 Seeland and Moen. 



By CHARLES LYELL, Esq., P.G.S., P.R.S., &c. 



[Read May 13, 1835.] 



A. PAPER was published by Dr. Forchhammer, of Copenhagen, in the 17th 

 number of the Edinburgh Journal of Science, July, 1828, in which he 

 seemed to have established the fact of a passage from the chalk into certain 

 tertiary strata, and to have proved it, not only by the occurrence of certain 

 species of fossil shells common to the one series and to the other, but also by 

 the alternation of strata, each exhibiting the mineralogical characters respect- 

 ively belonging to the chalk and the more recent deposits. 



The above-mentioned conclusions were drawn from observations made 

 nearly fifteen years ago, at a period when little was known of the geology of 

 Denmark, especially of the organic remains of that country ; it is right there- 

 fore to state at once, that Dr. Porchhammer has since changed his views on 

 the principal points which I am about to discuss. 



The following was the series of superimposed formations originally imagined 

 by Dr. Porchhammer to occur in Denmark : first, beginning with the oldest 

 group in Seeland, white chalk with flints in the cliffs of Stevensklint, with the 

 usual chalk fossils ; next above a seam of bituminous clay and other strata, 

 consisting of yellow limestone, in which occurred fossils of genera " usually 

 considered characteristic of tertiary rocks". Thirdly, above these, in the 

 same cliff, a coralline limestone approaching more nearly to white chalk in 

 its fossils and mineral composition. It was then supposed that the white 

 chalk with flints occurring in Mben, and containing the ordinary chalk fossils, 

 was still newer than the limestone last mentioned, and yet this same Moen 

 chalk was said to alternate, and to have been deposited contemporaneously, 

 with masses of clay and sand containing boulders*. 



It was impossible to read this statement without being convinced, that the 

 cretaceous rocks of Denmark must present some very singular and anomalous 

 appearances : I was therefore desirous in 1834 of visiting Seeland and Moen, 



* Edinburgh Journal of Science, No. 17, p. 67. 1828. 

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