236 ME. J. W. I). KOBINSOX on [vol. lxxvi,. 



Bibliography. 



A bibliography l up to 1880 appears in the Bulletin de la Societe 

 Geologique de France, ser. 3, vol. viii, pp. 483 et seqq. Since that 

 date the following papers have been published : — 



J. Gosselet. ' Etude preliminaire des Recents Sondages faits dans le Nord. 



de la France pour la Recherche du Bassin Houiller ' Ann. Soc. 



Geol. du Nord, vol. xxvii (1898) p. 139. 

 Do. ' La Faille d'Hydrequent ' Ibid. vol. xxxii (1903) p. 131. 

 Do. ' Considerations generales sur les Divisions & la Disposition du 



Terrain Devonien dans le Nord de la France & en particulier dans 



le Boulonnais ' Bull. Soc. Geol. France, ser. 3, vol. viii (1880) 



p. 491. 

 R. Zeiller. ' Sur les Empreintes Vegetales des Gres Devoniens de Caffiers ' 



Ibid. p. 501. 

 E. Rigaux. ' Notice Geologique sur le Bas-Boulonnais ' Mem. Soc. Acad, de 



Boulogne, vol. xiv (1889) 1892, p. 5. 

 Do. ' Le Devonien de Ferques & ses Brachiopodes ' Boulogne, 1908. 

 M. Mouelon. ' Considerations sur le Devonien Superieur (Famennien) de 



la Carriere du Bois de Beaulieu, &c. ' Ann. Soc. Geol. Belg. 



vol. xxxi (1904) p. b 214. 

 E. Maillieux. ' Etude comparative de la Repartition des Especes Fossiles, 



dans le Frasnien Inferieur, &c.' Bull. Soc. Beige de Geol. vol. xxiil 



(1909; Mem. p. 115. 



EXPLANATION OF PLATE XIV. 



Geological map and section of the neighbourhood of Ferques, on the scale 



of 3 - 125 inches to the mile, or 1 : 20,275. 



DlSCTJ,SSIOK\ 



Mr. L. D. Stamp congratulated the Author on the interest of 

 the district in which he had worked, and emphasized its importance 

 in a comparative study of British and Continental Devonian rocks. 

 The existence of a thrust-fault between the main tract of the 

 Devonian and the Carboniferous Limestone on the south elucidated 

 many difficulties. In Haut Banc Quarry, about 1 kilometre away 

 to the south, blocks of limestone with a typical Tournaisian fauna 

 had recently been found in a thrust-plane, proving the existence of 

 these beds in the district, although in the area described by the 

 Author only a small thickness of dolomites occurred below the 

 fossiliferous Visean limestone. The new thrust-fault found by 

 the Author showed that the absence of the Tournaisian and part 

 of the Famennian was due to faulting. Dip-faults or ' tears ' have 

 been proved in the Carboniferous to the south by Olry, 3 but his 

 maps showed them displacing the outcrop of the main thrust- 

 planes. Was it not possible that the dip-faults in the Devonian 

 continued into the Carboniferous, and were later than the main 

 thrusts ? The speaker did not think the evidence sufficient to 



1 A remarkable omission (especially as it contains a valuable map) is 

 Gosselet's ' Etude sur le Terrain Carbonifere du Boulonnais ' Mem. Soc. ScL 

 Agric. & Arts de Lille, ser. 3, vol. xi (1873) p. 7. 



2 Bull. Serv. Carte Geol. France, vol. xv, 1904. 



