348 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1914. 
When ferruginous elements under whatever form once exist in a 
stratum, they do not remain there unchangeable. The glauconite 
is altered, turns green, yellow, red. At the same time iron permeates 
neighboring oozes where it acts on the calcareous elements. There 
is then a transition to siderite, which itself may later be transformed 
into chlorite, then into hematite. 
These phenomena, begun beneath the sea and compelled from 
that time to form true ferruginous deposits, are continued, as we 
have seen in the case of the phosphates, in exterior alterations (by 
geologic processes) with gradual enrichment in iron because of the 
elimination of the more soluble calcareous elements which at first 
accompany them. You have then, at last, either some hematite, 
if alumina was lacking at the outset as is the case except when the 
glauconite is already associated with a calcareous ooze; or, when the 
point of departure was direct, an alumino-ferric silicate complex, 
like that ordinarily presented in our rocks, a red clay, retaining 
alumina associated with iron. The red clay and the iron ore proper 
may have, as can be readily understood, easy transitions from one to. 
the other. 
This study, as you see, throws a certain, though imperfect light 
on the important practical question of our sedimentary iron ores. 
And I would have you observe apropos, in passing, how pure science, 
science totally disinterested, which seems to have for its object only 
the search for truth, often has some useful results. 
It could not be foreseen that dredgings undertaken at the bottom 
of the sea would enlighten us on the origin of the ores of iron or man- 
ganese, and enable us, consequently, better to establish the theory 
of their formation, and finally to lead to borings at a great depth 
permitting the development, under conditions at first unforeseen, of 
an immense reservoir of iron like that which at this moment is 
making the fortune of Normandy.* 
2. MOVEMENTS OF THE BOTTOM OF THE SEAS—SUBMARINE 
VOLCANOES. 
The movements of marine bottoms are of two kinds. You might 
here see the slow displacements to which certain observations on 
our shores bear witness, or the deep subsidences of which geologic 
history offers us numerous examples. I could tell you of the cities 
of Ys and of those avenues of statues which on certain islands of 
the Pacific must have led in days of yore to some temple to-day 
engulfed beneath the sea. Not to bore you, I will confine myself, 
however, to some brief observations on volcanic phenomena. 
1 We could profitably discuss many other questions, particularly the intervention of glaciers in sedimen- 
tation, of which I wrote in La Nature, Oct. 5, 1912. 
