Revieics — E. Rigaux on the Boulonnais, 371 



name : witli the Bracliiopods we liave to translate the names sucli 

 as Zeilleria, Dicfyothyris and Eudesia into the more familiar and 

 customary Waldheimia and Terehratula. Some of the Gasteropods, 

 such as Hydatina, Diempterus, Diartema, Chenopus, Eustoma, Bigauxia, 

 Eligmoloxus, etc., would be wholly unintelligible to most geologists 

 were it not for their places in the lists. Some, at any rate, of these 

 names might have been put in brackets with the more general 

 generic names in front. It is impossible for a student to keep pace 

 with the minor changes of nomenclature, most of which should be 

 additions rather than alterations ; for important as these are to the 

 specialist, they are only a source of ambiguity to others. We do not 

 find fault with M. Rigaux in particular ; but we hope that he and 

 others will see, if not the error, at any rate the inconvenience of 

 their ways. For surely the object of scientific work should be to 

 lighten labour, and not unnecessarily to increase it. 



It is interesting to note that Terehratula globata is recorded from 

 both Great Oolite and Cornbrash, while Terehratula (DictyotJiyris) 

 coorctata is given as rare in the latter formation. 



The general succession of Oxfordian beds compares well with the 

 strata in this country. There are beds with Ammonites modiolaris, 

 and higher stages with A. Dmicani, A. MaricB, A. Lamherti, etc. No 

 doubt, as the author admits, he has included with his Oxfordian 

 division beds that in this country would be classed as Corallian ; of 

 these the limestone of IlouUefort contains several Corals, Cidaris 

 florigemma and other Echinoderras, Cliemnitzia (Fsendomelania) hed- 

 dingtonensis, and other species characteristic of our Corallian rocks. 

 Higher beds are grouped by M. Eigaux as Corallian and Astartian, 

 both of which divisions would also (he admits) be included in our 

 Corallian ; although the upper beds show, as in this country, the 

 incoming of Kimeridgian species. 



In the Kimeridgian stage are included representatives of Kimeridge 

 Clay and Portland Beds, the latter being, as the author suggests, the 

 littoral facies of the division. In the table at the end of the work 

 the " Portlandian " Beds are, however, grouped separately, but the 

 strata so-called mainly correspond with our Upper Portland Beds. 



The fact that each country must have its own minor divisions is 

 shown by the varying characters of the strata and the varying dis- 

 tribution of the fossils. 



Thus the ' Gres de la Creche ' (which comes beneath marls witli 

 Discina latissima) yields Neritoma siniiosa, Trigonia Pellati, Mytilus 

 autissiodorensis, Pterocera Oceani, Hemicidaris purbechensis, etc. 

 The ovei'lying ' Marnes a Discina latissima et Cardium morinicnm 

 yield Ammonites biplex, Belemnites Souichii, Exogyra (Ostrea) briin- 

 tnitana, Thracia depressa, etc. We should be inclined to group these 

 beds with our Lower Portlandian ; but M. Rigaux groups only the 

 succeeding ' Marne a Ostrea expansa ' with the " Portland Sands." 

 The same division is elsewhei'e marked as ' Marne a Perna Bouchardi,^ 

 and it contains some of the forms previously mentioned, also Astnrte 

 Scemanni, Cyprina implicata, Pectcn lamellosus, Discina latissima, and 

 Lingula ovalis. The highest Portlandian beds comprise the ' Calcaire 



