2 PLIOCENE MOLLUSCA. 



by Dr. W. Kobelt (1887-1908), Avitli a number of monographs by himself 

 and others in the ' Syst. Conch. Cab.' of Martini and Chemnitz. These and other 

 works which have thrown much light on Crag problems, together Avitli many 

 papers by various British and Continental Conchologists, will be constantly 

 referred to in the pages of the present memoir. 



I desire also to acknowledge, very cordially, my personal obligations to MM. 

 Dollfus, Dautzenberg, and De Boury of Paris, Prof. Peyrot of Bordeaux, Prof. 

 Welsch of Poitiers, the Marchese di Monterosato of Palermo, Prof. Sacco of Turin, 

 Prof. Issel of Genoa, Prof. Pantinelli of Modena, Dr. Fucini of Pisa, Dr. Eisig of 

 Naples, the late Prof. Seguenza of Messina, Dr. di Stefano of Reggio, Prof. Bucca 

 and Dr. Scalia of Catania, Mr. Clarence Bicknell of Bordighera, Mr. Van 

 Waterschoot van der Gracht of the Hague, Dr. Lorie of Utrecht, Dr. Tesch of 

 Nijmegen, MM. Bernays and van de Wouver of Antwerp, MM. Van den Broeck 

 and Rutot of Brussels, Prof, von Koenen of Gottingen, Prof. Br^gger and Dr. 0yen 

 of Christiania, Mr. Hermann Friele of Bergen, Dr. Jensen, Dr. Ravn and Dr. 

 Nordmann of Copenhagen, Prof. Nordgaard of Trondhjem, Dr. Sparre Schneider 

 of Troniso, Dr. Pjetursson of Reyjavik, Prof. Lonnberg and Dr. Odhner of 

 Stockholm, Dr. Dall of Washington, Mr. C. W. Johnson and Prof. Shinier of 

 Boston, U.S., Prof. H. Yabe of Sendai, Japan; and in our own country, to Dr. A. 

 Smith Woodward, Messrs. E. A. Smith, G. C. Robson and R. B. Newton of the 

 British Museum of Natural History, the Director of H.M. Geological Survey and 

 Dr. Kitchin, Prof. T. McK. Hughes, Mr. F. R. Cowper Reed, Prof. P. F. Kendall, 

 the Rev. S. N. Harrison, Canon Norman, the Rev. A. H. Cooke, Mr. J. R. le B. 

 Tomlin, Dr. Scharff, Mr. E. R. Sykes, Mr. P. G. H. Boswell, Mr. W. M. Crowfoot, 

 Mr. 0. Grabham of the York Museum, Mr.F. Leneyof the Castle Museum at Norwich, 

 Mr. Woolnough of the Ipswich Museum, Major Moore, the Messrs. Ogden and 

 others, who have assisted me in the most generous way, and especially in providing 

 specimens for comparison, and permitting me to figure them where desirable. 

 As to the non-marine Mollusca I have gladly availed myself of the expert 

 knowledge and the writings of Messrs. Kennard and B. B. Woodward, and of 

 Mr. J. W. Taylor, the author of the ' Monograph of the Land and Freshwater 

 Mollusca of the British Isles ' ; to them also my best thanks are due for much 

 friendly information and assistance. For the details here given as to the distri- 

 bution of such forms in the Pleistocene and Holocene deposits of Denmark and 

 Sweden I have to thank Dr. Nordmann. I have been able, moreover, to avail 

 myself of the long experience and accurate knowledge of Mr. Alfred Bell, who, 

 except for Messrs. Crowfoot, Dowson, and the writer, is the only survivor of those 

 who had the privilege of working with Searles V. Wood. To the memory of the 

 latter and of his equally distinguished son whose friendship I enjoyed for so 

 many years, I affectionately dedicate the following pages. 



The continued study of the Crag beds is not only desirable, but likely to prove 



