ORGANIC DEPOSITS 



939 



Average Composition of the Skeletons of marine Invertebrates and of Calcare- 

 ous Algce, estimated for Murray Island, Australia 



Corallinacere , 



Halimeda 



Mean alga 



Madreporaria 



Alcyonaria 



Mollusks 



Tinoporiis 



Amphistegina 



Orbitolites 



Polytreina , 



Approximate average foraminif era 

 Crustacea : 



( 1 ) Malacostraca and ostracods 



(2) Balanus 



Sea-urchin spines 



Worm-tubes 



CaCOs. MgOOa. CaSO,. CaaPaOs. 



80.00 

 99.00 

 89.50 

 99.30 

 75.00 

 99.75 

 89.00 

 95.20 

 89.40 

 88.75 

 89.50 



77.00 

 98.50 

 90.00 

 91.00 



19.00 



.50 



9.75 



.70 



15.00 



.25 



11.00 



4.80 



10.60 



11.25 



10.50 



12.50 

 1.50 

 9.00 

 8.00 



1.00 

 .50 

 .75 



1.25 

 1.00 



8.00 



8.75 



Chemical Composition of Corallinacew from Murray Island and Cocos-Keeling 



Islands 



(By Alfred A. Chambers) 

 Chemical analyses of calcareous algse 







OonioUthon 







OonioUthon 



orthoUastum 



Lithophyllum 





frutescens 



(Heyd.), 



Jcaiseri 





Fosl., 



M. A. Howe, 



Heyd., 





Cocos-Keeling 



Murray Island 



Cocos-Keeling 





Islands. 



Australia. 



Islands. 



Tj09^ on iernitioii 



46.70 



50.97 



45 72 



S5iO-.+FeoOo-l-AloOQ 



.07 



.11 



.28 



CaO 



46.16 

 6.29 



42.39 

 5.71 



45.92 



MgO 



7.09 



p„o. 



Present. 

 None. 



Present. 

 None. 



Present. 



SO3 



None. 







Total 



99.22 



' 99.18 



99.01 



CO2 needed 



43.19 



39.59 



43.88 







Reduced analyses (hypothetical combinations) 



Si02,(Al,Fe)203 



MgC03 



CaCOs 



CaaP^Os 



CaSO^ 



Total . 



0.07 



13.80 



86.13 



Trace. 



.00 



100.00 



0.12 

 13.66 



86.22 



Trace. 



.00 



100.00 



0.29 



15.33 



84.38 



Trace. 



.00 



100.00 



