Meviews — Radiolaria from Triassic Rocks. 429 



li E "V I E •VvT S. 



Eadiolakia from Teiassic and other Roces of the Dutch East 

 Indian Archipelago. By Dr. George J. Hinde, F.E.S. pp. 44, 

 with 6 plates. [From Dr. Eogier D. M. Yerbeek's "Report on the 

 Geology of the Moluccas" : Jarb. v. h. Mijnwezen in Nederlandsch 

 Oost-Indie, vol. xxxvii (1908).] 



THE rocks containing the Radiolaria described in this memoir were 

 obtained, some years since, by Dr. R. D. M. Yerbeek from the 

 islands of Timor, Rote (Rotti), Savu, Ceram, Celebes, Burn, and 

 Mangoli. These Radiolarian rocks are very similar in character to 

 those already known from other countries. The greater number are 

 of chert or hornstone, either light grey, reddish, or jaspery, apparently 

 entirely siliceous, and, as seen in microscopic sections, filled with 

 Radiolaria, now, for the most part, in the condition of casts, showing 

 merely the outlines of the organisms. In other cases the I'ock is 

 siliceo-calcareous, the Radiolaria in these retaining their siliceous 

 character and occasionally their structural details. Radiolaria are 

 also present in other rocks, mainly, if not entirely, composed of 

 limestone, and containing large numbers of Halohia, but in these, 

 as a rule, the Radiolaria are very imperfectly preserved and, for the 

 most part, replaced by calcite. Exceptionally, however, some of the 

 tests remain siliceous, with their outlines clearly defined, although 

 their interior structures have disappeared. 



Geological Age. — The association of the Radiolarian rocks in Rote 

 and Savu with beds of limestone filled with the shells of characteristic 

 Molluscan genera, Halohia (Bronn) and Baonella (Mojsisovics), and in 

 one locality in Savu with the Belemnite genus Asterocoiiites (Teller), 

 is satisfactory evidence that the rocks in question belong to the horizon 

 of the Upper Trias. If this conclusion is confirmed, an additional 

 importance will be attached to the Radiolaria from the rocks of these 

 islands as representing forms characteristic of this geological period. 

 Fortunately, many of the Radiolaria in these Upper Triassic beds on 

 Rote and Savu are fairly well preserved, and most of the forms 

 described and figured in the paper have been obtained from them. 



With regard to the geological age of the boulders and pebbles of 

 Radiolarian rocks occurring in secondary positions on the islands of 

 Ceram, Mangoli, Buru, and Celebes, very little is known at present. 

 The rocks from Ceram are considered by Dr. Wanner to be probably 

 Triassic, and a similar age is assigned to those from East Celebes. 

 Those from Buru and Mangoli are considered to be younger, probably 

 Jurassic or Lower Cretaceous, but they are of less importance, as the 

 Radiolaria in them are too poorly preserved for specific identification. 

 Detailed descriptions follow of the position and general characters of 

 the Radiolarian rocks from different localities, with a list of the genera 

 recognised in them. To this is added a description of the genera 

 and species, illustrated in the six large octavo plates. A summary 



