132 llev lews — Crela ceons S il ic i'^ponfi ia\ 



description of the Schrammen Collection in the American Museum 

 of Natural History, and a bibliography of over two hundred works, 

 finishes what is not merely an account of the Schrammen Collection 

 in America, but much more, a very complete introduction to the 

 study of Cretaceous Sponges as a whole. 



It is hardly a just cause for complaint that the authoress's 

 nationahty appears in her writing. No Englishman who loves his 

 land would refer, in speaking of the Dover district, to the " nearby 

 cliffs along the Kentish coast" (p. 59). " Arkosic " (p. 81) is a 

 strange word ; and " Cretacic ", however defensible, is both strange 

 and uglv, and does not appear to be used in any sense difi'erent 

 from the familiar '' Cretaceous ", unless it is that Cretacic is 

 American Cretaceous ; for " Cretaceous " is used, e.g. on pp. 52, 

 61, and 84, as well as in the title of the paper. '' Disconformably " 

 for " Unconformably " is unfamiliar. The following misprints 

 have been noticed : " Morven " (p. 62) apparently should be 

 '■ Morvan " ; on p. 72 " northern " is evidently a misprint for 

 " southern " ; on p. 91 " cornea " should be " carnea " ; and on 

 p. 154 '■' Acorchordonia " should be " Acrochordonia ". On pp. 150, 

 188, etc., " Gallo'pegnia acaulis " is written for " C. acaule ". 



Since the book under review is ostensibly a work on Sponges, 

 this is hardly the place to criticize in detail the stratigraphy 

 expounded on pp. 47-97. But this otherwise admirable resume 

 is somewhat marred by the fundamental misunderstanding of 

 the " zone ", apparent generally, but explicit in the remark (p. 52) 

 "as in all such faunal work, the cephalopods, being pelagic, are 

 considered the most reliable in the establishing of zones of Hmited 

 vertical, but wide horizontal extent, for which reason the standard 

 zonal subdivisions of the Cretaceous are based upon the 

 Ammonites ".^ Now, if I read its founder, Oppel, rightly, the 

 " zone " is that sediment (if any) which was deposited during a 

 eiven time in the earth's history. For convenience, it is named 

 after a fossil occurring in it (not necessarily throughout it) in one 

 locality (almost necessarily not all over the world). How, then, can 

 a zone be referred to relatively as "of wide horizontal extent ", 

 when a zone is necessarily worldwide ? And how can " zonal 

 subdivisions " be '' based upon Ammonites " when only their names 

 are based upon fossils ? (It may also be remarked that to imply 

 that Ammonites were pelagic is an assumption, even if it is generally 

 true that other Cephalopods are and were.) 



The authoress also appears to think that the zone of Pecten asper 

 in the South- West of England is usually included in the Albian 

 rather than in the Cenomanian, for on p. 57 she writes : "I shall 

 include therein [in the Cenomanian] the Warminster fauna of the 

 Pecten asper zone, since it would otherwise be difficult to compare 

 with the figures for entire faunas on the Continent, where the 



1 The division,by Grossceuvre, of the Chalk into zones named after Amm onites 

 is o-iven in tabular form, with correhitions, on p. 50. 



