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coarser^ more regular portion. It is_, indeed, only the first and 
excessively thin tubnliferous shell that is essential to this kind 
of Poraminiferal animal, which may grow and enlarge with 
this coating only ; but usually, when it has attained some size, 
and is favourably situated, the shell is thickened by supple- 
mentary layers secreted at the surface by sarcode-threads 
passing through ; and these, either straight, winding, or 
branched, wide-spreading or brush-like, keep passages open 
in the shell; hence the supplementary^^ or ^‘^intermediate 
skeleton,^-’ or vascular system,^^ varying in development 
among Poraminifera and in individuals, according to circum- 
stances. Thus every patch of Eozoon seems to have flourished 
with thickened shells, layer on layer, for a time, as shown by 
the laminee of calc-spar permeated by branching threads 
(figs. 1, 6, 7, 8) ; and then the sarcode formed its innumerable 
gemmules and segments with less and less of the extra coat- 
ing, until only the essential shell-wall, delicate and minutely 
tubular (figs. 5, <i, 9, 10), separated more or less perfectly the 
heaped-up granular segments (fig. 3), and is now best recog- 
nized in the delicate velvety film of minute whitish perpen- 
dicular threads coating the dark-green granules. 
The presence of this well authenticated Poraminifer in 
these lowest and oldest rocks clears away the error of re- 
garding the Metamorphic rocks as paving been formed 
originally otherwise than as sediments like sand, mud, and 
shell-rock, and the error of terming them ‘^‘Azoic,^^ or life- 
less. They might, perhaps, be termed “ Eozoic,"’^ as suggested 
by Dr. Dawson, if we may regard the Eozoon as really a 
creature of the dawn — but who knows? We are not sure 
these rocks are Primary in the strict sense of the word ; 
indeed, they were made from the ruins of older rocks, probably 
once sediments themselves. Perhaps we had best keep to 
Palseozoic,^^ for they are old enough for certain. But is 
Eozoon alone in these deposits? Dr. Dawson says that he 
sees other things, like bits of Crinoids and Shells, and traces of 
Worm-burrows, in the Laurentian schists and limestones. 
The graphite too, and apatite, and iron-salts were probably 
not all due to Poraminifera alone, however widely and thickly 
spread. The curious, chambered Eozoon seems to have been 
filled with silicates of magnesia, alumina, &c., just as Porami- 
nifera are filled in like manner with a silicate of alumina 
(glauconite) in the present seas, and as they have been filled 
in all seas Tertiary, Secondary, and Silurian; the differing 
contents of the sea-water at so widely distant times giving 
different silicates ; and, thus preserved, their forms are found 
strewing the bed of the Mexican Gulf and of Australian and 
other seas in profusion. And further, thus accumulated, they 
