Chemical Composition of Recent and Fossil Lingule.. 237 
cess of ‘0075 over the amount required to form the phosphate, 
and corresponding to ‘0134 of carbonate; the small amount of 
sia; the results from the calcined shell of Lingua ovalis are then 
as follows: : 
Phosphate of lime, ‘0978 = 8579 p. centum. 
Carbonate of lime, . ‘0134 = 11-75 
Magnesia, - = 0032 = 280 
1144 = 10034 
The proportion of phosphate of lime is that contained in hu- 
man bones, after their organic matter has been removed. 
- The texture of the ancient Lingule was observed to be unlike 
that of most other fossi! shells, being more or less dark brown in 
color, brilliant, almost opaque, and not, at all crystalline. ‘These 
same dark color and brilliancy were also remarked in the genus 
Conularia, and the shell of C. trentonensis, proved on examina- 
tion to be composed in like manner of phosphate. — 
The similarity of composition in these genera Is In accordance 
With the acute observations of Mr. Hall, who finds that Conula- 
ra is almost always associated with Lingula and Orbicula, and 
remarks that “these shells so unlike in structure and habit, ap- 
pear-to have flourished under similar circumstances, and to have 
required the same kind of ocean bed or sedimeut.”—Paleontol- 
By, vol: i, p. 1U1. 
For the sake of comparison, we have examined the following 
fossil shells : they have a common character, distinct from those 
already described, being lighter colored, more translucent and 
granular in texture; Atrypa ertans, Leptena alternata, aud Or- 
this pectenella from the ‘Trenton limestone ; O. erratica from the 
Hudson River group, and Chonetes lata ? from the Upper Silu- 
tan, besides Isotelus gigas, anda species of Cythere trom the 
Trenton. All of these consist of carbonate of lime, with only 
Such traces of phosphate as are generally found in calcareous 
shells, 
In the Report already quoted we have given a description of 
Some ‘phosphatic bodies which resemble the coprolites of the 
Calciferous sandstone, and are found at Riviére Ouelle in thin 
yers of a conglomerate limestone, which is in with 
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