554 Revieics — Harris and Burrows — Paris Basin Mollusca. 



palgeontologists in England. Its Proceedings have become the 

 depository of a most valuable series of Memoirs ; the records and 

 illustrations of its excursions, which extend to Belgium, France, 

 and Italy, form a volume by themselves ; and having, if we may 

 assume, exhausted the geology and palaeontology of their own 

 country, they are attacking and peacefully re-conquering the 

 aRcient country of France, by publishing, in a separate form, a 

 Memoir on the Eocene and Oligocene Beds of the Paris Basin. 

 The authors of this work have qualified themselves for the task by 

 repeated careful examinations of the French Tertiary area, and one 

 of them by an extended traverse over other parts of the Tertiary 

 formations of Europe. They justify the special study of the 

 French Tertiaries on the ground " that no adequate conception can 

 be formed as to the meaning and value of our own Tertiary beds and 

 their organic remains without conjointly studying those on the other 

 side of the Channel — especially in regard to the paleeontological 

 aspect of the subject." Tliey point out that the Mollusca have 

 always afforded the best basis for correlating the several horizons 

 in France, Belgium, and England, by reason of their abundance, 

 their wide distribution, and the very perfect state of preservation in 

 which they occur, especially in the Paris basin ; so that the French 

 area supplies, as it were, the key by which to open up and interpret 

 correctly the sequence and life-history of other Eocene and Oligocene 

 strata in neighbouring areas. 



The authors deal especially with the Mollusca, and in order to 

 equip themselves thoroughly for the task, they have worked very 

 carefully and critically over the great French collection acquired 

 from G. P. Deshayes some forty years since, and preserved in the 

 Geological Department of the British Museum (Natural History). 

 Tliese specimens bear, in almost every case, Deshayes' original labels, 

 and therefore form a valuable basis for fixing their nomenclature 

 even where, as in so very many instances, these names have now to 

 be exchanged for more modern and presumably more correct deter- 

 minations. They have also visited and examined the chief collections 

 in Continental Museums. 



Pages 1-44 of this Memoir are occupied with a carefully prepared 

 description of the Eocene and Oligocene Beds of the Paris Basin, 

 well illustrated with sections at Issy ; at Cuise-la-Motte ; at Arcueil ; 

 at Auvers; near Ver, on the road to Ermenonville ; at La Chapelle- 

 en-Serval ; at Butte d'Orgement ; and Quarry of Yintue, near Etrechy. 

 In each, the lithological characters of the several beds are clearly 

 given, as well as the typical Mollusca which mark each horizon. 

 This is followed (pp. 44-56) by an Outline Guide to the principal 

 sections and fossiliferous localities. Here is useful practical advice 

 to collectors (p. 45). " A word or two as to the collection of fossil 

 may be useful. Strong calico bags of various sizes, but mostly large, 

 say 12 in. by Tin. to Tin. by 4in. are the best receptacles for fossils, 

 and they should be so made that the mouth can be drawn together 

 and tied by tape. A brass ring sewn on enables several bags to be 

 threaded on a strap and carried with ease, without fear of breaking." 



" Sift ! is the watchward in the Paris area, as the smaller species of 



