EEPOKT ON THE DEEP-SEA DEPOSITS. 
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flattened. They are insoluble in hydrochloric acid. The small quantity of material at 
our disposal did not permit of complete analysis, but we found them to contain silica, 
magnesia, and iron. The external characters show on a small scale so many of the 
peculiarities of the chondres of meteorites, that celebrated experts in meteoric stones 
pronounced them as such without being aware of the source from which they were pro- 
cured. These characters may be best realised by reference to the figures on PI. XXIII. 
Fig. 11 represents the external aspect of one of these spherules from a Globigerina 
Ooze, Station 338, 1990 fathoms. South Atlantic. It was procured from the residue 
after treating about two quarts of the deposit with dilute acid. It is about 1 mm. in 
diameter, being magnified twenty-five times in the figure ; it is yellowish brown, but the 
bronze metallic reflection is not rendered in the figure. At the upper part a shallow 
depression or cupule is seen. The internal structure is leaf-like, excentric, and more or 
less radial, and is seen to consist of the apposition of fine lamellse. It might be said 
that these lamellse take their origin from a centre situated near the left hand side of the 
spherule. This radial, excentric, lamellar structure is one of the characteristics of the 
chondres of meteorites ; indeed, this structure has been considered diagnostic of chondritic 
forms of bronzite, for example. Microscopic examination by means of transmitted light, 
however, only partially confirms this relationship with the chondres of bronzite. The 
small size, as well as the friability, of these spherules, make it impossible to cut them 
into thin sections ; we were, therefore, limited in our examination to splinters obtained 
by breaking these little bodies between two glass slides. In consequence, however, of 
their lamellar structure they break into extremely thin plates that are perfectly transparent 
except at those points where there are numerous dark, opaque inclusions, believed to 
be titaniferous magnetite. Under a magnifying power of 200 or 300 diameters, the 
details shown in figs. 10 and 13 can be observed. These thin plates are almost colourless, 
or at most they are slightly brownish, and present two systems of crystalline lamellse. 
Both of these systems are formed by little prisms, grouped in a parallel fashion, which 
on crossing cut each other at angles of about 70° and 110°, as represented in fig. 10. 
The small prisms juxtaposed in a parallel manner, and forming what we have called a 
system, all extinguish at the same time ; their colours of polarisation are not very 
pronounced. 
When we published the preliminary results of our researches some years ago, it was 
stated that these prisms always extinguished following their longer axis ; later measure- 
ments, which we consider as quite definite, have shown that this observation was not exact. 
Belying upon the preliminary observation, we believed that they belonged to the rhombic 
system, but by operating upon little detached prisms we have observed that while in the 
great majority of cases the extinction followed their longer axis, in others the little 
prisms are extinguished under a maximum angle of 40°. The lamellae are thus crystallised 
in the monoclinic system. 
