SCIENTIFIC SUMMARY. 
431 
form of a cone or cylindrical strobilus *12 metre long and *055 metre wide ; 
it shows externally the summits of scales which form 27 perfectly regular 
longitudinal rows, disposed in spiral order represented by the fraction 
a disposition not unlike that of many living Lycopodiaceae. The further 
details of M. Brongniart’s paper are too numerous for further abstract. The 
paper may be read in the Comptes JRendus, August 17. 
A new Classification of Echmidce . — M. A. Pomel, who has been for some 
time preparing a comprehensive memoir on the fossil Echinoderms of Western 
Algeria, has prior to its publication submitted his new classification of 
Echinidae to the consideration of the Academic des Sciences (Aug. 3). The 
Echinidae, he says, present three types, which progress regularly from the 
bilateral {symetrie paire) to the radiate symmetr}*, and form three groups, to 
which he has given the name of Spatiform, Lampadiform and Glohiform. 
The first have the mouth placed very excentrically in front, and the anus 
lies posteriorly ; the obliteration of the anterior ambulacium and the 
obovate form mask the radial symmetry to the advantage of the bilateral. 
The second have the mouth central, or very nearly so, and the anus less or 
more posterior, but close enough to the genital parts to enter into that series. 
The third have the mouth central and the anus opposite and included in 
the genital apparatus. The Spatiform or Spatangoid Echini form two 
gTOups: (1) Ananchytce where the ambulacra are throughout represented 
by simple pores. (2) Spatangce^ where the ambulacra are petaloid. The 
Lampadiformae are grouped into dentate and edentate. Lastly, the Globi- 
formae include the Cidaridae and Echinidae. The other divisions of M. 
Pomel’s scheme will be found in the paper already referred to. 
Precis elementaire de Geologic . — The eighth edition of this treatise, by 
M. d’Omalius d’Halloy, has been published. 
The Constitidion of the Interior of the Globe . — Few questions possess 
greater interest for the geologist than this one of the internal constitution 
of the globe. Few too display greater discrepancy of opinion in the 
history of the science. Many years ago Mr. Hopkins adopted an astrono- 
mico- mathematical argument to show that the facts of precession and 
nutation were incompatible with the theory that the globe was a liquid 
mass, enclosed in a thin solid crust. His views have since been very largely 
accepted. But they have now met with a formidable opponent in M. 
Delaunay, one of the foremost mathematicians and astronomers in France. 
In a memoir — which we wish we had space to translate in full — M. 
Delaunay goes at length into Mr. Hopkins and Archdeacon Pratt’s argu- 
ments and. arrives at the provisional conclusion that the astronomical 
evidence adduced tells as much on one side as on the other, and that in 
point of fact the problem is now as unsolved as when it first presented itself 
to men’s minds. This expression of opinion on M. Delaunay’s part must 
have great weight with geologists. — "Vide Comptes Rc7idus, July 13. 
The Chalk of A7itrmi.— M.Y. J. Beete Jukes, of the Irish Geological Survey, 
states that the upper surface of the Antrim chalk is covered with a layer of 
flint gravel, from one to six feet thick, and over this lie thick ranges of 
columnar basalt. The flints when broken open are found ‘Ho exhibit 
concentric bands of various tints of red surrounding a grey interior, and 
coated by an external white envelope.” This reddening of the flints had 
