150 llie A))ierican Geologist. March, i&sts 
the small globular bodies from the Eozoonal limestones of the 
Ottawa valley found by Sir J. W. Dawson and described 
under the name of Archjeospherina.* Compare them also with 
those obtained from the Protolenus (or Ellipsocephalus) hori- 
zon of the Cambrian rocks at St. John, N. B., found by W. D. 
Matthew\f 
Descripfioii of the Rddiohtridiis. 
"It was in June, 1892, that Dr. Barrois placed in my hands 
[Cayeux] sections of the phtanites and quartzites that he had 
collected in the neighborhood of Lamballe (Cotes-du-Nord) 
in which he had observed circular sections, recalling those of 
radiolarians. Though the circular form was there, the struc- 
ture was not apparent. After a very minute examination I 
recognized some traces of hexagonal reticulate structure, fa- 
voring the hypothesis that the slides contained radiolarians; 
and not only so, but I thought I recognized very primitive 
forms belonging to the Monosphterida." 
For two years M. Cayeux gave himself to the careful micro- 
scopic study of these phtanites and was able to confirm the 
first observations by the "discovery of a complete fauna of 
siliceous rhizopods, remarkable for the great number of indi- 
viduals and of genera which it contains. The number of 
shells found has been very great," and he has published a 
plate of 45 forms of these pre-Cambrian radiolarians. 
Mr. Cayeux would not publish liis work until he had sub- 
mitted the slides to those interested, including foreign learned 
specialists, who, though not agreeing with his conclusions, 
admitted that the forms were organic. Two of the persons 
specially referred to are Mr. G. ,). Hinde, of London, and Mr. 
Eiist, of Hanover. 
The difficulty of the inves^tigation of fossil radiolarians may 
be inferred from the statement of the latter savant in his 
memoir on the Triassic; and Paheozoic radiolarians, that he 
had made more than 5,000 thin microscopic sections to obtain 
200 forms of radiolarians in a good state of preservation; and 
Mr. Caj^eux declares that he himself was not much more for- 
tunate — and he adds that one of his slides is of more interest 
*Geol. Mag. London, voL ii, p. 334. Also "LitVs Dawn on K;irili,"" 
by J. W. Dawson, London, 1875. p. 137, fig. 33. 
fOn Phosphate Nodidos from Ihc Cambrian rocks of SoutluTn New 
Krunswiok. Trans. N. York Acad. Sci., April, 18t)3. p. 114, pi. 3. 
