242 J. B. Scrive)ior — Radiolarian Rochs, East Indies. 



were pre-Cretaceous ami probably Jurassic, and Professor Molengraaf 

 was of tbe opinion tliat the ]u-esence of the E,adiolaria, combined 

 with the fi'reat extent of the beds containing them, at least 230 kilo- 

 7uetres, stamped those beds as deep - sea deposits. Professor 

 Molengraaf, however, is careful to say tliat the presence of pelagic 

 organisms alone is not conclusive proof of oceanic deposits, " for we 

 know that in certain localities close to the coast where, through 

 peculiar conditions, the deposition of terrigenous materials on the 

 ocean floor was entirely or almost entirely prevented, even at a short 

 distance from the shore, deposits are found which may be composed 

 exclusively of remains of pelagic living organisms." These conditions 

 were thought too unlikely to extend for 230 kilometres. On p. 418 

 Professor Molengraaf says in a footnote that the sandy shales and 

 clay-slates are too much folded and disturbed for liim to say with 

 certainty whether they lie on top of or below the chert, but they 

 appeared to be above it. Finally, after sketching the extent of the 

 Danaii formation, Professor Molengraaf refers to some deposits in 

 Sambas, a province of West Borneo, with the same trend as the 

 Danau formation and comprising a eon:plex of cherts.^ He adds : 

 " Should the cherts of Sambas prove to be of the same age as those 

 of the Danau formation, Radiolaria will doubtless be found in them if 

 searched for." 



In 1904 Mr. Wing-Easton's work- on part of West Borneo, 

 including the greater part of Sambas, was published. Kadiolaria 

 were found in Upper Triassic, Jurassic, and Cretaceous rocks, many 

 being located in Sambas, but the rocks containing them are not 

 described as cherts as understood by us. Thus, on p. 25 we find in 

 connexion with tlie Upper Trias : "On the other hand there are in 

 the vicinity of the quartz-porphyries hard beds ricli in silica and often 

 with Radiolaria, which must be explained as ashy deposits of the 

 above-named eruptive rocks, and which are veiy like quartzites when 

 light-coloured or ' kieselschiefer ' when dark." These Upper Triassic 

 beds are referred to again on p. 233. On pp. 271, 272, and 275 

 Jurassic rocks with Kadiolaria are mentioned. It is stated that 

 lladiolaria occur in a hard rock which can only be determined as 

 a 'kieselschiefer'. jS'o mention is made of ' hornstein ' or ' radio- 

 larienjaspis ' except in reference to Professor Molengraaf's rocks 

 (p. 40).^ The other Jurassic rocks containing Radiolaria are marl 

 and limestone. Among the Cretaceous rocks Radiolaria were found 

 iu marl, limestone, siliceous propylite-tutf, and sandstone. The most 

 important remarks, however, that Mr. Wing-Easton makes about the 

 Radiolaria-bearing beds are to be found on pp. 40 and 41, where it is 

 emphatically stated that the Jurassic and Cretaceous beds were 

 deposited in shallow water near a coast, and the same view is held, 

 apparently, for the Upper Triassic rocks. 



Nevertheless, Professor Molengraaf in his 1909 paper does not 

 (j^ualify his previously expressed views about the deep-sea origin of 



1 p. 421. 



- " Geologie eines teiles von West Borneo" : Jaarb. v. li. Mijnwezen m 

 Nader. Oost-Indie, Weten. Gedeelte, 1904. 



^ Verbeek, however, uses ' kieselschiefer ' for chert. See below. 



