Reviews—Browne’s Ice-caves of France and Switzerland. 451 
the reach of external influences. It would be interesting to know 
the relation of the ice-caves to their different planes of temperature. 
If they occur in regions where the winter is long or very severe, 
and the summer. short or very mild, and at such a distance from 
the surface that seasonal changes do not affect them, then it is quite 
easy to understand how ice would be found in them. It would be 
well if explorers would direct their attention a little to this matter. 
The prismatic structure of the ice, so common in the glaciéres, is 
another interesting subject of enquiry. The Frenchman’s sugges- 
tion at Bath, that it might be something akin to the rhomboidal 
form assumed by dried mud, we believe not to be far from the mark. 
But whether the desiccation results from heat or great cold, we 
cannot determine. We would associate with these other phenomena 
having, as we believe, a similar origin—as, for instance, the columnar 
structure in basalt, which has nothing whatever of a crystalline 
structure in it. It is curious to observe that basaltic prisms occur 
in exactly the same relation to the altered substance as do the prisms 
of ice—that is to say, in beds extending from the one surface to 
the other, and in cylindrical columns radiating from the centre to 
the circumference. ‘The same cause produces the columns in wheaten 
starch. The walls of the vitrified forts in Scotland often exhibit 
beautiful specimens of the same structure in places where they have 
been subjected to great heat, though not sufficient to produce vitri- — 
fication. We have also seen very beautiful and remarkably regular 
pentagonal and hexagonal columns produced in the brick floor of a 
baker’s oven which had been Jong in use, and consequently sub- 
jected to frequent and considerable changes of temperature, though 
never sufficient to produce fusion. And we have often gathered 
good examples of hexagonal columns from the exposed bituminos 
shale-beds at Wardie, near Edinburgh. 
III. ANALES DEL Musto Pusiico pE Buenos AIRES, PARA DAR 
A CONOCER LOS OBJETOS DE LA Histor1a NATURAL NUEVOS 6 
POCO CONOCIDOS CONSERVADOS EN ESTE ESTABLECIMENTO. Por 
GERMAN BurMeisTER, M.D., Ph.D. Buenos Aires, 1865. (4to., 
pp. 85, with six Plates.) 
HE illustration, by Burmeister, of the cranial and of these 
dental characters of the Macrauchenia patachonicha not pre- 
viously known, renders both interesting and instructive a retrospect 
of the steps by which a knowledge of this remarkable and anomalous 
extinct form of hoofed quadrupeds has been acquired. 
In 1836, the fossils brought home by Darwin from South America, 
in H.M.S. Beagle, were submitted to Owen for determination and 
description. ‘They were numerous, mostly fragmentary, and from 
among them were selected certain limb-bones and vertebra, which 
were associated together as belonging to the same animal, and re- 
ferred to a new genus and species, for which the name Macrauchenia 
patachonicha was proposed. Of the zoological position and affinities 
of this animal, Owen states—‘ In the Unculate series there are but 
two known genera—the Rhinoceros and Paleotherium—which, like - 
GG 2 ; 
