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composition. The pressure of the beds in course of formation would then 
fill up the lower half of the mould, forming the cast in relief. The Cruziance 
consist essentially of two convex parts united in the middle line, and 
marked on the surface with oblique sinuous striae. Their extent renders it 
impossible to trace their whole length, or to obtain an entire individual 
with the superior termination of the frond. Nevertheless, from a number of re- 
markable impressions collected by Professor Moriere of Oaen, we see that the 
lines of junction, which are at first simple, afterwards become complicated 
by ramification, and produce at the summit a goffered, sinuous expansion. 
At many points on the surface of the phylloma of Cruziance scars of inser- 
tion are observed, which seem to be produced by radicles or organs of 
fructification, leaving, when shed, the traces of their attachment. 
The Eophyta are cylindrical bodies (stems or pliyllomata). They are 
more or less elongated, perhaps ramified above, or dilated and laterally com- 
pressed, and always marked with regular striae and fine channels running 
longitudinally, and often resembling nervures. They have no resemblance 
to the Cruziance, and the two types must have constituted distinct genera, if 
not families. Neither of them can be regarded as nearly related to any 
existing Algce, but they may be regarded as extinct types very distantly 
allied to the Caulerpese. — (Assoc. Prang. pour VAvancem. cles Sciences, Seance 
de 1878, p.576.) 
Volcanic Products at the bottom of the Pacific . — The Abb6 Renard, and 
Mr. J. Murray communicated to the Geological Section of the British Asso- 
ciation, at Sheffield, the results of an examination of the materials brought 
up by the Challenger's instruments from the bottom of the central Pacific. 
The area from which the materials submitted to the Abbe Renard were 
derived, extends from the Sandwich islands to 30° S. lat., having the Low 
Archipelago approximately in its centre. Volcanic matter was found to 
play an important part in the formation of the bottom, being present in the 
form of lapilli and ashes distributed in great abundance in the “ red clay,” of 
which we have heard so much. The lapilli nearly all belong to the basaltic 
type, passing from felspathic basalt to allied rocks, in which the vitreous 
base acquires greater and greater development, until it almost entirely dis- 
places the crystalline constituents of the basalt, when the fragments become 
mere glassy rocks of the basic series, generally containing some crystals of 
peridote, innumerable crystallites, the latter sometimes grouped in opaque 
granules, sometimes arranged regularly around the peridote microlites. 
From the forms of these volcanic fragments, which are often coated with 
manganese, their association with volcanic ash, and their lithological consti- 
tution, they cannot be derived from submarine flows of lava. They are 
rather incoherent volcanic products, or lapilli, the accumulations of which in 
the Pacific form a series of submarine tuffs. 
One of the most remarkable facts, brought to light by these soundings in 
the Pacific, is the large share taken in the formation of these sedimentary 
deposits by palagonites, perfectly identical in lithological characters with 
those of Sicily, Iceland, and the Galapagos islands. Many are in fact glasses 
of the basic series, either consisting of sideromelane, or decomposed into a 
red resinoid substance. The small lapilli of two or three inches in diameter 
are cemented by zeolites, showing the crystalline forms of christianite. 
