596 
NATURE 
[Aprit 18,.1907 
‘“ Glimpses of Australian Bird-life’’ is a praiseworthy 
attempt to encourage the study of the avifauna of the 
island-continent among field naturalists. The photographs, 
although on a small scale, are for the most part excellent, 
while Mr. Robert Hall’s brief explanatory notes are (as 
might be expected) v« much to the point. One of the 
most interesting species depicted is the whip-bird (or 
coachwhip-bird), while from the point of view of excellence 
in technique, special mention may be made of the portrait 
of the so-called reed-warbler and its nest. Ree. 
NOTES ON RECENT PETROGRAPHY. 
STUDENTS of the processes of sedimentation and of 
flocculation in clays should not overlook the three 
papers on sands and sediments, by Messrs. Mellard Reade 
and Philip Holland, that have been published in the 
Proceedings of the Liverpool Geological Society. 
original analyses of sediments given in the second paper 
(vol. x., part i., 1905), and in the third now issued (1906), 
are distinctly valuable. Some of the specific gravities 
stated for clays seem a little high; but it must be admitted 
that we possess as yet far too little knowledge of our 
commonest sedimentary deposits. In vol. x., part ii. 
(1906), p. 136, the authors point out that ‘‘ the experi- 
ments have, we think, demonstrated the existence of a 
mass of matter of unsuspected granular minuteness dis- 
tributed throughout the sedimentary rocks of the earth. 
. . . We have strong grounds for thinking that the dis- 
tribution of the finest sediment, in the form of what we 
may call quartz-dust, is oceanic.’’ The abundance of 
quartz grains in some rocks popularly classed as argil- 
laceous, such as ‘‘ slates of coarse texture’’ (p. 156), is 
of course already familiar to agricultural investigators. 
Mr. H. W. Nichols, in describing new forms of con- 
eretions (Field Columbian Museum Publications, Geo- 
logical Series, vol. iii., No. 3, 1906), usefully brings to 
the front Forchammer’s determinations of magnesia in 
the skeletons or shells of marine organisms, which were 
originally published in 1849. Mr. Nichols supports these 
by analyses of his own (pp. 48-9), Corallium rubrum 
giving him 932 per cent. of magnesium carbonate. 
Forchammer’s Mediterranean Serpula yielded as high a 
figure as 7-64 per cent. The Zoantharia examined give 
only trom 0-35 per cent. to 0-54 per cent. 
Messrs. Allen, Wright, and Clement have experimentally 
investigated the minerals of the composition MgsSiO, 
(American Journal of Science, vol. xxii., November, 1906), 
and have produced artificially the two pyroxenic types, 
monoclinic and rhombic, and the corresponding two amphi- 
bolic types. At atmospheric pressure (p. 415), the mono- 
clinic pyroxene, MgSiO,, a rare form in nature, is found 
to be the product of crystallisation from solvents; the 
material used for this experiment may be any of the forms 
of crystalline MgSiO,. All the other forms of magnesium 
silicate (p. 437) pass into the monoclinic pyroxenic form 
at temperatures between 1150° and 1300°, depending on the 
erystal-form employed. Enstatite crystallises at lower 
temperatures than the monoclinic pyroxene. The amphi- 
bolic types have been produced by a rapid cooling, which, 
as the authors point out, is not likely to be the prevailing 
cause of their occurrence in natural rocks. 
Mr. H. I. Jensen, in dealing with the volcanic area of 
the East Moreton and Wide Bay districts, Queensland 
(Proc. Linnean Soc. of New South Wales, 1906, p. 73), 
describes a number of trachytes containing riebeckite, some 
of which form important plugs or domes. Trachytes, as 
well as basalts, are recorded from Gough Island, in the 
South Atlantic, by Messrs. Pirie and R. Campbell (Proc. 
Royal Physical Soc. of Edinburgh, vol. xvi., 1906, p. 258). 
Mr. I. G. Sundell (Bull. Comm. géol. de Finlande, 
No. 16, 1905), writing in English, or American, affirms 
the importance of cancrinite as ‘‘a very abundant and 
doubtless primary constituent ’’ of the syenites of the 
parish of Kuolajarvi in N. Finland. His paper, like 
many others from various parts of the world, shows the 
strong influence already exerted by the Chicago system 
of classifying igneous rocks. 
Mr. G. K. Gilbert (Bull. Geol. Soc. America, vol. xvii., 
1906, p. 321) discusses gravitational assemblage in 
NO. 1955, VOL. 75 | 
The: 
granite, citing striking cases, from. the Sierra Nevada, 
where large crystals of felspar and hornblende have re- 
spectively assembled in aggregates in granite. An example 
of banded granite, where bands rich in hornblende and 
mica alternate with others rich in felspar and quartz, 
suggests to the author successive sedimentation. Uncon- 
formities occur in the banding (p. 324), a dark band 
always forming the base of the upper series, and trun- 
cating obliquely the edges of previous bands. Mr. Gilbert 
puts forward the view, as a hypothesis, that a pair of 
bands represents a unit of deposition from the original 
magma, gravitation playing a réle in the process. 
Mr. R. A. Daly, of Ottawa, whose work in the field 
of igneous absorption and intermingling is well known, 
states his case of the Moyie Sill in the Purcell Range 
with effective lucidity in the Festschrift zwm siebzigsten 
Geburtstage von Harry Rosenbusch (Stuttgart, Schweizer- 
bartsche Verlagsbuchhandlung, 1906). His contribution is 
entitled ‘‘ The Differentiation of a Secondary Magma 
through Gravitative Adjustment,’’ and his argument for the 
assimilation of a felspathic quartzite-series by a gabbro- 
magma is supported by a number of chemical analyses. 
A granite zone intervenes between the gabbro and the 
overlying part of the quartzite-series, and the author holds 
that (p. 225) ‘* there is clear chemical proof that the 
greater proportion of the elements in the granite could 
have been derived directly by fusion of the quartzite.” 
The gabbro, in its onward passage, absorbed beds » of 
quartzite, but (p. 228) ‘‘ simultaneously gravitative adjust- 
ment has nearly restored the original composition, as the 
acid, assimilated material rose through the denser gabbro 
magma to the top of the sill.’” We need not subscribe as 
yet to Mr. Daly’s view (p. 233 and previous papers) that 
the pure igneous magma in the earth’s crust is of basic 
composition, since there may be a variety of pure magmas 
in a variety of localities; yet we believe that there is 
much soundness in his concluding sentence :—‘‘ The fact 
of ‘consanguinity’ among the igneous rocks of a_ petro- 
graphical province may be due as much to assimilation as 
to differentiation.”’ GSA ene 
ARCHAZOLOGY IN ITALY. 
THE final rejection by the Italian Government of Prof. 
Waldstein’s well-advertised project for an international 
excavation of Herculaneum gives the Rome correspondent 
of the Times food for reflection with regard to the alleged 
Chauvinism of Italian archzologists, who will allow no 
foreigner to take part in Italian excavations, notwith- 
standing the fact, which they admit freely enough, that 
Greco-Roman antiquity is the property of the whole world, 
and not of Italy alone. While admitting that the postpone- 
ment of the excavation of Herculaneum until such time as 
Italy can do it by herself does not much matter from the 
scientific standpoint, since ‘‘ the treasures which lie beneath 
Resina are in safe keeping, and might remain undisturbed 
for centuries,’’ the correspondent remarks that this is by 
no means the case with regard to other sites, which cry 
aloud for speedy excavation, for valuable evidence is in 
their case being destroyed daily by the ‘‘ march of modern 
improvement.’’ To do the work, Italy can muster neither 
suflicient money nor sufficient men, especially the latter. 
Yet she will not invite foreign aid, which would willingly 
and gratefully be given by archaeological students all over 
the world. As the Times correspondent is obliged regret- 
fully to admit, ‘‘ The foreigner is at liberty to pay his 
lira for admission to museums and other places; he may 
even give a round sum for the completion of some worl 
in which he is interested, as long as he does not wish © 
help in carrying it out himself; he may turn his tale’ 
to such use as advertising the achievements of Ital 
archeologists or translating their books into anet’ 
language ; he may show an intelligent and devoted inter” 
but it must be from a discreet distance. That, at lk - 
seems to be the moral of all the recent relations betw ° 
Italy and other countries in the archaeological questi ‘ 
which have come to the front during the last twenty years 
or so. One would willingly believe it otherwise; one 
would gladly put a more literal and liberal interpretation 
on their professions of confraternity ; but how is it possible 
