264 
GEOCHEMISTRY: CLARKE AND WHEELER 
11. Waldheimia cranium. Lofoten Islands. Analyses 10, 11, by L. 
Schmelck.^ 
Older analyses of calcareous brachiopods 
6 7 8 9 10 11 
SiOz 0.60 ? 
FeaOs trace 0.40 0.15 
MgCOs trace 1.05 3.40 .... 1.20 1.40 
CaCOa 98.39 94.60 87.80 96.20 96.20 95.58 
CaS04 2.40 2.15 0.90 0.85 ? 
CaaPzOs 0.61 .... 0.28 0.18 
SrO .... .... .... trace 
CaO 0.30 
MgO 1.80 0.60 
P2O6 trace 0.12 
Organic matter 1.00 2.55 4.30 2.00 1.24 1.99 
100.00 100.60 99.73 100.18 100.49 99.64 
With these analyses ours agree in a broad, general way, although the 
older ones vary much as regards completeness. Kunckell's analyses, 
showing free Kme and magnesia are suspicious, but only in this detail; 
otherwise they have confirmatory value. All the analyses show that 
this group of brachiopods have shells in which calcium carbonate is the 
principal constituent, and 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 which respect if recalculated to a common 
basis, Kunckell's analysis agrees approximately with ours. Rhyncho- 
nella is also interesting for the reason that an analysis by Hilger of 
shells purporting to belong to this genus are made to be phosphatic, 
and practically identical in composition with those of Lingula. The au- 
thenticity of Hilger's material is questionable; and his analysis will 
not be reproduced here. 
In the group of phosphatic brachiopods four analyses have been made 
by us. On account of the large amount of organic matter in these 
shells, 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. 
1. Lingula anatina, Gmelin. Coast of Higo Province, Japan. Or- 
ganic matter, rejected, 40%. 
2. Lingula anatina, Iloilo, Philippine Islands. Organic matter, re- 
jected, 39.5%. 
3. Discinisca lamellosa, Broderip. Coast of Peru. Organic matter, 
rejected, 25%. 
4. Glottidia (formerly Lingula) pyramidata, Stimpson. Coast of 
North Carolina. Organic matter about 37%. Analysis incomplete for 
lack of sufficient material. 
