July 27, 1900.] 



SCIENCE. 



149 



Becken ' is Murray's 'Gazelle Basin,' his 

 ' Japanischer Graben,' the famous ' Tuscarora 

 Deep,' and his ' Atlantische Schwelle' include 

 the 'Dolphin,' 'Connecting' and ' Challenger 

 plateaus of Murrays maps. One consequence 

 of the difference in method is that but six of 

 Supan's names are identical with those of 

 Murray, although thirty-nine of the former 

 and fifty-six of the latter relate to the same 

 portion of the sea-bed. Such a state of 

 affairs needs immediate attention if confusion is 

 to be avoided in the future. Some of Supan's 

 terms, e. g., ' Chilenisch-Peruanisches Becken,' 

 are, at the least, inconvenient ; the ' Nord- 

 meer Becken ' ' Murray's Arctic Basin ') is to 

 the Anglo-Saxon ear possibly ambiguous. 

 Yet, on the whole, Supan's names are well 

 chosen. 



In the two systems sharper definitions of the 

 terms 'plateau,' 'swell,' 'ridge,' 'bank,' 'rise,' 

 'trough,' and 'basin' are necessary. As yet 

 we have no clear statement as to the character- 

 istic features of any one of them. Size, shape, 

 depth and slopes should have some sort of limi- 

 tations for each type, and, difficult as it may be 

 to set bounds where one type passes into 

 another, yet, for purposes of presentation and 

 of understanding the subject of submarine 

 topography, we believe that the attempt should 

 be made. In any case, it is manifest that we 

 have not, at the present time, secured a com- 

 plete list of even the larger forms of the sea- 

 bottom. The recent discoveries of the ' Moser 

 Deep,' the 'Nero DeBp' and the ' Reykjanaes 

 Ridge,' the last-mentioned is the best known of 

 all the great basins, show this conclusively. 

 When, in addition, we reflect that the lesser 

 details of suboceanic relief are yet to be deter- 

 mined, we may well ask if the future more or 

 less complex system of nomenclature should be 

 definitively impaired by too close adherence to 

 the doctrine of priority, or, on the other hand, 

 by a too hasty acceptance of new views. What 

 is needed is a classification of forms which will 

 include not only those already discovered but 

 also the many expected in future exploration. 

 It is to be hoped that the committee will suc- 

 ceed in finding out the right way. In one re- 

 spect their task is comparatively light ; if 

 changes in the existing nomenclature are neces- 



sary, they will now meet with a minimum of 

 prejudice either academic or of other sort. The 

 habit of but one generation, and, indeed, of but 

 a few of the world's broadest and best trained 

 scientific men needs to be affected in order to 

 secure a firm foundation upon which may be 

 based a classification suitable for needed ex- 

 pansion. 



THE LITHOLOGY OF ANCIENT MARINE SEDI- 

 MENTS. 



Attention should be called to the elaborate 

 ' Contribution a 1' etude micrographique des ter- 

 rains sedimentaires' by Cayeux (Memoire de la 

 Soc. Geol. du Nord, t. iv, Mem. No. 2, Lille, 

 1897). He concludes, after a painstaking study 

 of the Cretaceous sediments of France and of 

 England, that the chalk must be regarded as 

 having been deposited in comparatively shallow 

 water. It is thus important to note that the 

 doctrine of Continental permanence is not in- 

 validated by this latest and most detailed ex- 

 amination of the London and Paris Basin beds. 

 Cayeux proposes to add to our classification of 

 oceanic sediments by recognizing, with the ter- 

 rigenous and pelagic deposits, a third class, the 

 ' benthogenic,' which are composed principally 

 of the remains of bottom organisms. Examples 

 are cited in the bryozoal beds of Senonian lime- 

 stones and in the Cretaceous strata made up 

 essentially of sponge spicules, his ' spongolith.' 

 He discusses at length the problem of glauconite, 

 and finds conclusive evidence that it may be 

 found either by the intervention of decaying 

 animal matter or by simple secondary crystalli- 

 zation in the absence of organic substance. 

 He lays stress on a new class of ancient marine 

 sediments distinguished from the more usual 

 sandstones by the presence of a high pro- 

 portion of silica soluble in alkalies (allied to 

 opal). While the rock may consist of from 76 

 to 92 per cent, of silica, no more than 50 per 

 cent, is clastic quartz, the rest of the silica 

 being accounted for by this soluble diagenetic 

 form. This type of sandstone, the ' gaize ' of 

 French geologists, Cayeux would have perma- 

 nently introduced into our classification of 

 sediments. 



Reginald A. Daly. 



Harvard University. 



