R. Bullen Newton — Foratninifera from New Guinea. 203 



Furthermore, with respect to the non-metallic elements, some 

 regions are characterized by excess of fluorine, others by excess of 

 boron, each giving rise to characteristic groups of minerals, which 

 indicate the chemical composition of the original magma. The 

 further significance of these facts will be discussed more fully at 

 a later stage. 



The following table shows the chief minerals found in ten of the 

 more important wolfram-tin ore-deposits in different parts of the 

 world : — 



{To he continued.) 



IE. — FoRiMINrFKllAL AND NULLIPORE StRDCTIJEES IN SOME TeRTIARY 



Limestones from New Guinea. 



By Pi. Bullen Newton, F.G.S., Geological Department, British'Museum.^ 



(PLATES VIII AND IX.) 



Introdoction. 



AT the request of Professor J. W. Gregory, F.R.S., of Glasgow 

 University, the following report has been prepared dealing with 

 some microscopical organisms entering into the composition of certain 

 limestones from Central New Guinea. The material studied, com- 

 prising Foraminifera and Nullipore [Litliothamnium') remains, has 

 been obtained from some rolled limestone pebbles which were 

 collected in river-beds of the upper reaches of the Fly Eiver by 

 the Kight Hon. Sir William Macgregor, G.C.M.G., during an 

 expedition carried out in the years 1889 and 1890. Being desirous 

 tliat these limestones should be scientifically examined, Sir William 

 submitted them to the Geological Department of tlie University 



^ Published by permission of the Trustees of the British Museum. 



