( 532 ) 



of pseudoglacial to all kinds of bosses and scratches wliicli elsewhere 

 would scarcely be so called, because they do not in the lerst resemble 

 the striae of glaciers '). 



This absence of positive characteristics is however easily explained. 

 Leaving alone the fact that as yet no thorough investigation of the 

 subject has been made, the condition of the Ardennes themselves 

 are very unfavorable to research. Its dense forests, fens and heaths 

 make it dilTicult to reach the surface of the rocks, ^vhose harder 

 layers are only capable of preserving marks. The reason why so 

 few traces are found on the sides of the valleys and on the plateau 

 of the Meuse becomes plain, when we remember that during the 

 period following the receding of the Northern glacier, the waters 

 of the Meuse rose 200 M. abo\'e the level of the sea, and not only 

 filled the whole valley but inundated the plateau of the Meuse and 

 thus destroyed the traces left by the glacier. 



Of this we find the clearest proofs in the terraces which have 

 retained their boulders. ') Besides, exactly the same thing happened 

 with the Rhine and its tributaries. The sand and small pebbles 

 carried along by their waters must necessarily have almost entirely 

 obliterated the marks of the glaciers left on the rocks '). 



Striae, however, are not the only evidences of the action of a 



1) X. Stainier. Stries pseudo-glaciaires en Bolgiquo. Bull. Soc. beige de Geologie 

 X. Briixelles 1896. Pr. verb. p. 212—216. 



E. VAN DEN Broeck. Contiibutioiis a l'étude des phénomènes d'altéralions 

 dont rinterpi'étation erronée pourrail faite croire a l'existanee de stries glaciaires. 

 1, c. Xni. 1899. Mém. p. 323-334. PI. XX. 



G. SiMOENS. Sur line rocbe présentant des slries pseudo-glaciaires en Gondroz. 

 1. c. Pr. verb. p. 222-223. 



2) É. DupoNT et M. MouRLON. Explication de la feuille de Dinant. Bruxelles 

 1883, p. 100. 



A. RuTOT. Résnllals de quelques explorations dans ]e Quaternaire de Ia Meuse. 

 Buil. Soc. beige de Geologie. XIV. Bruxelles 1900. Pr. vorb. p. 259, 260. 



X. Stainier. Le cours de la Meuse depuis l'ère tertiaire 1. c. VIII. 1894 Mém. 

 p. 84. PI. VII. 



E. VAN DEN Broeck. Goup d'oeil synthélique sur l'Oligocène beige et les obser- 

 vations sur Ie Tongrien supérieur du Brabant I.e. Vil. 1893, p. 255, 256, 266. 



E. VAN den Broeck. Exposé somtnaire des observations et découvertes stratigra- 

 phiques et paléonlologiques faites dans les depots marins el fluvio-marins du Lim- 

 bourg pendant les années 1880—81. Ann. Soc. roy. raalacolog. de Belgique XVI, 

 Bruxelles 1881. Buil. p. GXXV-GXLII. 



3) It might be suggested that the transport of these boulders had taken place by 

 means of icefloes, but Mr. Lohest has demonstrated in the most positive manner 

 that these ice-masses are incapable of effecting a notable removal. He comes to 

 the conclusion that among the present climatic conditions no explanation can be 



