244 



PKOCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 24, 



The Conchifera from the " Crag jaime " and " Crag gris " are the 

 same ; the differences are solelj^ in respect of the gasteropods. The 

 distribution in depth of the living analogues of the Crag conchifers 

 will satisfactorily explain this ; and the only other inferences which 

 these tables suggest are, 1st, that the species generally indicate a 

 greater depth of water, as their life-zone, than that of remanie Scal- 

 desien beds in which they occur ; and, 2nd, that these deeper 

 zones of the Crag-sea had very decided southern or Lusitanian 

 relations. 



M. Nyst is of opinion that the marine fauna of the lower Diestien 

 beds (Crag noir) is more nearly allied to that of the Paluns of 

 Bordeaux, Piedmont, Sicily, and Austria, than that of the Scaldesien 

 Crag. This view is hardly supported by a consideration of the 25 

 species of Conchifera which occur in the Edeghem and Fort Herenthal 

 zone. As the product of the shallower-water sea-zones which con- 

 tributed the Scaldesien fauna, shows decided southern relations, the 

 deeper- water zones would necessarily show a like relation somewhat 

 more strongly, from the more uniform conditions which obtain there. 

 This is just what happens now. This impression as to the Falunien 

 facies of the lower Crag is very likely to suggest itself, from the pre- 

 sence of corals such as Stephanophyllia, Flahellum, and the marked 

 preponderance of such genera as Cancellaria, Fusus, Pleurotoma, 

 Conus, many of which are so very like Barton and Rupellien species 

 as to give an even older aspect to these beds. All the Diestien spe- 

 cies are, however, distinct, and these resemblances are good illustra- 

 tions of that system of representation which is to be observed in 

 respect of the products of like conditions and zones of depth of every 

 geological period. 



M. Nyst's list of Edeghem shells may be reduced from 145 to 

 130 in respect of uncertainties ; of these 47 are known as living. 

 This gives a seemingly larger proportion of unknown to known 

 forms than is the case with the Scaldesien Crag. The question which 

 arises is, whether this diiference is connected with relative age, — 

 whether it is any proof that the Edeghem beds are of greater anti- 

 quity than the Scaldesien. Geologists have so considered it. 



The 47 species above referred to are as follows,^ — L. signifying 

 Lusitanian province, Br. British, B. Boreal. 



Table III. 



Chemnitzia simiHs, Forbes. L. 

 Pyramidella plicosa, Bronn. L. 

 Odostomia plicata, Broc. B. & S. L. 



10-70 f . 

 Actaeon tornatilis, Lin. B.-L., 3-60 f. 

 E-ingicula buccinea. L., 4-60f. 

 Natica millepunctata, Lin. L. litt.-40f. 



Josephinea = OUa. L., 8-12 f. 



Cypreea pyrum, Chn. L., uncertain. 

 Europaea, Mont. B. & L., litt.- 



20 f. 

 OHva flammulata. West Afr. 



Mitra fusiformis, Broc. L. 

 Aporrhais pes-pelecani, Li7i. B.-L., 



100 f. 

 Pleurotoma intorta, Broc. 

 Nassa incrassata, Mull. B.-L., litt.- 



50 f 

 Cassis Saburon. L.-W. Africa, 8- ?. 

 Calyptrgea sinensis, Lin. S, Br,-L., 



litt.-lO f. 

 Crepidula unguiformis. L. 

 Emarginula fissura, Lin. 

 Dentalium entalis, Lin. L., 2-200 f. 



