19"-] STEVEXSOX— FORAIATIOX OF COAL BEDS. 617 



When he looks at the dune surface, he sees, as it were, shrubs rising 

 out of the sand, some short thick stems of beech and oak ; but they 

 are not shrubs, they are the still living parts of trees, the same in 

 age and growth as those standing in the open forest. They have 

 been buried by the advancing dune. A mighty storm tiood, tearing 

 away the sea wall and removing part of the dune, will expose vertical 

 trees standing in the sands as in the Coal Measures sandstones. At 

 present, one sees advancing masses of sand burying the trees, which 

 grow on low-lying moors. At another locality, storms, during re- 

 cent years, have exposed an older peat deposit, underlying the sands 

 of the Rostock plain. The outcrop extends hundreds of meters 

 along the shore and shows that the peat is a moss peat, which bore 

 a forest of Scotch fir. There, as also near Graal, the waves hav^ 

 torn off fragments of the peat and have worn them down into 

 elliptical form similar to that of the beach pebbles. Barrois^^^ has 

 referred to similar origin of peat pebbles on the shore of the British 

 channel, where some neolithic deposits of peat are exposed to the 

 waves. The fragments of peat are rolled, rounded and eventually 

 transformed into true ellipsoidal pebbles. 



Lorie,^"* in his fifth contribution to the surface geolog}' of Hol- 

 land has gathered together all the available information respecting 

 the buried recent peat deposits of that region. 



In all probability the Zuyder Zee was filled with peat prior to 

 the catastrophe of the middle ages, but the only vestige is on the 

 island of Schalkland, where one finds 5 to 7 meters of peat covered 

 with a meter or more of marine clay. The same condition exists 

 on the river Y near Amsterdam and in the province of Zeeland as 

 well as in the west part of North Brabant in Belgium. The peat 

 bed near Oudenbosch, in the latter province, is 0.75 meter thick and 

 underlies 0.65 meter of sediment. It is readily traceable from that 

 village across Zeeland into western Flanders of Belgium, and thence 

 to the coast at Ostend in Belgium and Dunkerque in France, a dis- 



'^ C. Barrois, " Observations sur les galets de cannel-coal du terrain 

 houiller de Bruay." Aim. Soc. Gcol. du Xord., Vol. XXXVII., 1908, p. 7. 



^^ J. Lorie. " Les dunes interieures, les tourbieres basses et les oscilla- 

 tions du sol." Archives Mus. Teylcr, 2me Ser., Vol. III., 1890, pp. 424-427, 

 444. PI. 2. 



215 



