﻿Reviews — Foraminifera of Belgium. 327 



The synonymy of the sub-divisions is as follows : 



Panopoea Menardi Sands : (Black) Ecleghem Sands. 



Pectunculus pilosus Sands : Shelly glauconitic Sands, Dumont and 

 Dewael ; Black Sands of Fort Herenthals, Nyst, 1843 ; Black or 

 Lower Antwerp Crag, Lyell and Dewael : Black Antwerp 

 Sands, Omalius d'Halloy, Dujardin, and Mourlon. 



Gravelly Sands of Antwerp and Diest. 



Gi'een Sand, Dujardin, Mourlon, and Cogels ; Diestian System, 

 Glauconitic Diestian Sand. Ferruginous Sand and Grit, Dumont; 

 Diest Sands, Omalius d'Halloy, d'Archiac, Lyell, Dewalque, 

 and Mourlon. 



Throughout the formation of this series subsidence was going on 

 to the N.W. and emergence to the S.E., so that each zone overlaps 

 the N.W. edge of its predecessor, but does not reach its S.E. border. 



The Middle and Upper Antwerp Sands (corresponding to the 

 English Coralline and Red Crags respectively) follow, and will be 

 described in a future memoir. 



As against the placing of the -Lower Sands in the Miocene or 

 terming them Diestian, it is urged that the break between the 

 Oligocene or L. Miocene and the Lower Sands is greater than any 

 break in the whole Antwerp Series, and the principal break in 

 the latter is between the Middle and Upper divisions, both ad- 

 mittedly Pliocene (Scaldisian).' 



Lists of fossils of the Lower Sands are given, relative abundance, 

 range, etc., being shown. With a caution as to the eifect of bathymetric 

 dififei'ences and the incompleteness of our knowledge of the existing 

 fauna, the relative numbers of extinct and recent species are stated 

 to be as follows : Panopoea Menardi zone 44: per cent, recent ; 

 Pectimculus pilosus zone 51 per cent, recent, or on the average 47 

 per cent, for the whole. 47 per cent, occur in the English Coralline 

 Crag, and 51 per cent, in the English Crags generally. 



The Lower Sands range from N. France into Holland and N.W. 

 Germany, but there is no evidence that they ever extended into 

 England, as the pebbles of rock of that age in the Basement Beds 

 of the Coralline and Red Crags may have been derived from the 

 Belgian area. Traces of the Gravelly Sands occur on the Kentish 

 Downs (these are regarded by Mr. Whitaker as probably Eocene, see 

 Mem. London Basin, p. 336). 



Errors have arisen from the alteration of the glauconite in these 

 beds, and from the removal of the shells by percolating waters, an 

 important discovery made independently by English and Belgian 

 observers in 1876. The shells are first rendered friable and then 

 completely removed by carbonated waters (occasionally leaving 

 impressions and casts), whilst the glauconite is decomposed first into 

 pale-green protoxide, and finally into deep red-brown peroxide of 



^ A trivial objection is made to the use of the term Black Crag, that the deposit is 

 unrepresented in England, and is therefore not Crag. But by use and wont " Crag" 

 is all but s3'rioaymous with Pliocene, and similar exception might be taken in every 

 case where a foreign series bears the name of its less-developed British equivalent. 



