444 The American Naturalist. [May, 
Jurassic. 
Organic matter. 
Oxide of iron. 
Phosphoric acid. 
Flourine of apatite. | 
Ratio 
A. Oolithic. 
lac ‘ 
ya ‘lime, iron pyrites, s ged silica Saath od se 17.25 | 0.68 | 6.40 
Licsuabadeestes 0.56 0.57 | 0.98 
. Teleosaurus cadomensis. Bon State from 1 
sulphate of lim: red in notable fr a lit de 
ey k E aries KEA ae BENNE P anes PEE IEC Ree a piel: aan 
lophorus. _— c calcaire 0 
Cerin (Department of Ta mprints of fishes. A 
| 0.90 | 34.97 | 2.31 | 3.12| 0.74 
ellow T, 
lightly dnte with yellow and Carbonate of | 
e in notable quantity, traces o chlor ine, no silica...... 11.62, 1.05 | 33.94 
B. Lias. 
4. Ichthyosaurus burgundia. Vertebra from the su- 
ae lias of Saint Co rng ent of Yonne). 
rty gray, im s! rele h, remaining same 
color after i on, rey due to the abun- 
dance of car! mate of of eee traces of chlorine, 
a ep pA {faded “i roe pi of me ‘and ‘sulphate of lime 
the middle lias of 
Posh twig i cham ree a with white, strewed 
; breaks ana pul 
a 3.03 | 0.62 
} 
En EER sss] | By i x i k 0.98 
. Teleosaurus of lias. icone’ reddish-brown, becom. gcse Sarees pointes yere Pie s 
gray, arros by ignition 
much carbona te of lime, a little ie ahien mad and by ignition ; | 
of sulphate of lime and pyrites of iron, chlorine wy «| 13.88 | 4.65 | 10.57 
lesiosaurus. Vertebra of the lower lias of V 
oa Bib 
y 
ance of carbonate of thane more than thea average q 
tity of chlorine, a little silica, 
vn 15.24 2.73 | 14.79 2.19| 1.31 | 1.67 
Average of the seven Jurassic specimens: 
Phosphoric acid, elites i ; 17.79 
Fl nes es ty 
uorine, 1.44 no Ratio, 0.91. 
Fluorine calculated for ARN AR 
