BRACHIOPODS. 



37 



For comparison the following unalj^ses of calcareous brachiopods, made elsewliere, are 

 significant : 



6. Terebralula ap. Collected by Pourtalfes between Florida and Cuba; S. P. Sharpies, analvHt."' 



7. Terebratulina caput serpenlis. Locality not given; F. Kunckell, analyst." 



8. Crania anoiiuila Miiller. Locality not given; F. Kunckell, analyst. 



9. M'aldheimia cranium 'MiiWeT. Locality not given; F'. Kiuickell, analyst. 



10. M'ahiheimia cranium. Collected by the Norwegian North Sea Expedition, station 255; latitu<ie, 08° 12' N.; 

 longitude, 15°40'E.; depth, fi24 meters; bottom temi)erat>ire, (1.5° C. 



11. W'aldheiinia cranium. Lofoten Islands. 

 Analyses 10 and 11 by L. Schmelck.-'- 



Older analyses of calcareous brachiopods. 



With these analyses ours agree in a broad, general way, although the older ones vary 

 much as regards completeness. Kunckell's analyses, showing free lime and magnesia, are 

 suspicious, but only in this detail; otherwise they have confirmatory value. All the analyses 

 show that brachiopods of thi.s group have shells in which calcium carbonate is the principal 

 constituent and that the proportion of organic matter is low. The only aberrant one is Crania, 

 which is noteworthy on account of its high percentage of magnesia. In this respect, Kunckell's 

 analysis, if recalculated to a common basis, agrees approximately with ours. Rhynchonella 

 is also interesting for the reason that an analysis by Hilger of shells supposed to belong to this 

 genus indicates that they are phosphatic and practically identical in composition with those 

 of Lingida. The authenticity of Hilger's material is questionable, and his analysis wall not 

 be reproduced here. 



Four analyses of shells of phosphatic bracliiopods have been made by us. As these shells 

 contain a large amount of organic matter, which possibly varies with the age or maturity of 

 the animal, we prefer to report our results, as others before us have done, in proximate rather 

 than ultimate form. The analj^ses are as follows: 



1. Lingula analina Gmelin. Coast of Higo Province. Japan. Organic matter, rejected, 40 per cent. 



2. Linqula analina. Iloilo, Philippine Islands. Organic matter, rejected, 39.5 per cent. 



3. Z)Mnni.scn Zc;m<;/?o.sa Broderip. Coast of Peru. Organic matter, rejected, 25 per cent. 



4. Olottidia (formerly Lingula) pyramidola Stimpson, coast of North Carolina. Organic matter, about 37 percent; 

 analysis incomplete for lack of sufficient material. 



Analyses of phosphatic brachiopods. 



SiO 



(Al,Fe)A 

 MgCOj... 



CaCOj 



CaS04 



Ca^P-P,. . 



0.91 

 .54 

 2.70 

 1.18 

 2.93 

 91.74 



0.50 



.29 



.79 



4.25 



4.18 



89.99 



0.85 

 .58 

 6.68 

 8.35 

 8.37 

 75.17 



0.49 

 1.16 

 1.71 

 (?) 

 (?) 

 74.73 



100. 00 100. 00 



100.00 



M Sharpies, S. I'., .\m. Jour. Sci., M ser., vol. I, p. I6S, 1871. 

 " Kunckell, F., Jour, prakt. Chemie, 2d ser., vol. m, p. 102, 1899. 



n Schmeick, L., Norske Nordbavs Exped., No. 28, p. 129, 1901, 



