502 ADDRESS OF T. STERRY HUNT. 
they had replaced the sarcode of the animal, precisely as glauco- 
nite and similar silicates have, from the Silurian times to the pres- 
ent, filled and injected more recent foraminiferal skeletons. I re- 
called, in connection with this discovery the observations of 
Ehrenberg, Mantell and Bailey, and the more recent ones of Pour- 
tales, to the effect that glauconite or some similar substance oc 
sionally fills the spines of Echini, the cavities of corals and mille- 
pores, the canals in the shells of Balanus, and even forms casts 
of the holes made by burrowing sponges (Clionia) and wore 
The significance of these facts was farther illustrated by showing 
that the so-called glauconites differ considerably in composition, 
some of them containing more or less alumina or magnesia, and, 
one from the tertiary limestones near Paris being, according t0 
Berthier, a true serpentine. * 
These facts in the history of Eozoön, were first made known by 
me iri May, 1864, in the American Journal of Science, and subse- 
quently more in detail, February, 1865, in a communication to the 
Geological Society of London. t They were speedily verified by 
Dr. Gümbel, who was then engaged in the study of the ancient 
crystalline schists of Bavaria, and soon recognized the existence, 
in the limestones of the old Hercynian gneiss, of the characteris- - 
tic Eozoin Canadense, injected with silicates in a manner precisely 
similar to that observed by Dawson and myself. { Later, in 1869, 
Robert Hoffmann described the results of a minute chemical exam- 
ination of the Eozoon from Raspenau, in Bohemia, confirming 
previous observations in Canada and Bavaria. He showed that 
the calcareous shell of the Eozoén, examined by him, had been eg 
jected by a peculiar silicate, which may be described as related iD 
composition both to glauconite and to chlorite. The masses of 
Eozoén he found to be enclosed and wrapped around by thin al- 
ternating layers of a green magnesian silicate allied to picrosminê, 
and a brown non-magnesian mineral, which proved to be a hy- 
drous silicate of alumina, ferrous oxyd and alkalies, related to 
fahlunite, or more nearly to jollyte in composition. § 
Still more recently, in the course of the present year, Dr. Daw- 
son detected a mineral insoluble in acids, injecting the pores of 
* Amer. Jour. Sci., Il, xl, 360, Report Geol. Survey Canada, 1866, p. 231, and Quar. 
Geol. Jour., XXI, 71. s 
ł Amer. Jour. Sci., IY, xxxvii, 431. Quar. Geol. Jour., XXI, 67 
} Proc. Royal Bavar. Acad. for 1866, and Can. Naturalist, new series IFI, 81. 
§ Jour. fur, Prakt. Chem., May, 1869, and Amer. Jour. Sci., III, i, 378. 
