350 Mr. Lyell on the Cretaceous and Tertiary 



four of the genus Cerithium, six of Pusus, two of Trochus, one of Triton, 

 one of Nassa, one of Bulla, and several others. There is also a Patella, 

 and an Emarginula. On the whole, there are more than thirty univalves, 

 spiral or patelliform, and not one of them is common to the Faxoe formation 

 and the white chalk. Yet of the Brachiopoda found with these, no less than 

 ten can be identified with species of the chalk, and there are an equal number 

 of Lamellibranchiate bivalves, which are identical. A still greater proportion 

 of sponges, corals, and other zoophytes found at Faxoe, agree with those of the 

 chalk, no less than forty-two having been identified out of 104 procured from 

 the two formations in Denmark. Of Crinoidea and Echinodermata, fourteen 

 species are ascertained to be common to the two formations, also two species 

 of Foraminifera, and two of Annelidas. 



The Cephalopoda of Faxoe deserve also particular mention, two of them, 

 Baculites Faujasii and Belemnites mucronatus, being common to the white 

 chalk and to Faxoe, and there being an Ammonite, as well as two species of 

 Nautilus in the Faxoe beds, a fact which some will consider as peculiarly in- 

 teresting, since so many carnivorous trachelipods are associated with these 

 cephalopoda*. 



The above statements will be sufficient to satisfy a geologist, that the Faxoe 

 fossils belong to the cretaceous period. The univalve shells which constitute 

 their peculiar character are not identical with any known tertiary species, and 

 have therefore merely a generic resemblance to tertiary fossils. 



It may naturally be asked, why so many univalves should be found in this 

 rock, whereas they are almost entirely absent from the white chalk. This 

 might be supposed to arise from one of two causes, first the local conditions 

 of the spot where the stone of Faxoe was formed, which may have been more 

 fitted for the existence and multiplication of univalve testacea ; secondly, 

 the stony matrix of Faxoe may have been more favourable for their pre- 

 servation. Both causes may have operated, but probably the latter has 

 been most influential, for the shells themselves have disappeared, even at 

 Faxoe, being only recognizable by casts, which the softer chalk might 

 not have retained. Dr. Beck has also pointed out to me a curious fact 



* I have been favoured by Dr. Beck with drawings, both of Cyprcea bultaria, and Nautilus Da- 

 nJcM5, Schlotheim, pp. 117 and 83, both from Faxoe specimens in the collection of H.R.H. Prince 

 Christian. A considerable degree of interest has been attached to N. Danicus, since Mr. Von Such 

 declared his opinion that it was specifically identical with Nautilus aganiticu^, Mont., which Count 

 Miinster, following Sowerby, calls N. sinuosus. (Leonhard and Bronn's Neues Jahrbuch, 1834, 

 p. 533.) Dr. Beck has, in our Proceedings, vol. ii. p. 218., denied this identity, and Schlotheim 

 had previously pointed out the differences. (Petrefactenkunde, p. 83.) The annexed figures 

 (Plate XVIII.) will enable the zoologist to form his own opinion on this subject. 



