DECEMBER 10, 1903] 
IAT ACRE 
Lao) 
portance in the comparison of forms, in the naming of 
species, and in the correlation of strata by their aid. As 
the author points out, it demonstrates the necessity for 
abundant material in palzontological studies. 
Mr. W. H. Dall has published a summary of the geo- 
logical results of the study of the Tertiary fauna of Florida, 
1886-1903 (Zrans. Wagner Inst. Sci., Philad., iii., part vi.). 
He points out the objections to the method of grouping 
which was based by Lyell and Deshayes on the percentage 
of species that survive to the present day, as the conditions 
may be more favourable for the survival of species in one 
region than in another. The presence or absence of 
identical species in the Tertiary beds on either side of the 
Atlantic may be an important factor in correlation, but 
while this is partially true of older geological horizons, yet 
after the Mesozoic epoch the faunal characteristics of the 
shallow-water Mollusca of different regions became rapidly 
distinctive. Even in the Eocene but two or three species 
can be claimed as identical on both shores of the Atlantic, 
and in later periods it would be unreasonable to expect to 
find a series of identical species in subtropical marine in- 
vertebrate faunas in widely separated regions. In order to 
establish correlation, we should look for equivalent stages 
of evolution in relation to preceding and subsequent faunas, 
and not expect a greater number of identical species than 
are found in the contemporaneous faunas of distant areas 
at the present day. Mr. Dall adopts the grouping of Eogene 
to include Eocene and Oligocene, and Neogene to include 
Miocene and Pliocene, and he gives detailed lists of fossils. 
He discusses the physical changes that have taken place, 
and agrees that no discontinuity of the link between N. 
ana S. America from the Miocene to the present time is 
probable, and certainly none amounting to a free com- 
munication between the two oceans. 
A pamphlet on “‘ Rock Phosphates and Other Mineral 
Fertilisers ’’ has been issued by Dr. Charles Chewings 
(C. E. Bristow, Adelaide, S. Australia). The object is to 
give descriptions of the deposits from which mineral 
fertilisers originate, with notes on the preparation of the 
phosphate for the market, as an aid to the prospector and 
to others engaged in the practical applications of the 
manures. Particulars are given of phosphate deposits in all 
parts of the world, but special reference is made to those of 
Clinton, on Yorke’s Peninsula, in South Australia. Here a 
cange of hills, formed mainly of Cambrian rocks, rises to 
an elevation of nearly 400 feet, and beneath the crest, in 
a N.E. and S.W. direction, the rock phosphate occurs. It 
extends for more than 104 chains, varies in width from 8 to 
20 chains, and is covered to a considerable extent by alluvial 
deposits. No fossils have been found in the deposit, and the 
author gives reasons for believing it to have been derived 
from guano. Selected samples can hardly be distinguished 
from the phosphate rock of Christmas Island. 
According to Mr. E. O. Hovey (Science, November 13) 
the ascending obelisk of Mont Pelée, of which we repro- 
duced an illustration from a photograph taken on June 13 
(NaturE, October 1), has since disappeared. Meanwhile, 
the dome of the cone surmounting the crater has been 
greatly altered, and a small spine issued from it early in 
September. This was pushed up 20 metres within a 
week, and then destroyed by an eruption. Eruptions giving 
rise to great dust clouds led to the expectation that further 
Serious disturbances might take place. The latest bulletins 
(October 1 to 19), however, indicate only feeble activity of 
the volcano. 
We have received the subject list of works on the mineral 
industries and allied sciences in the Library of the Patent 
Office. This is a helpful guide to the literature of various 
subjects, and these are arranged under headings of which 
assaying, clay and clay industries, coal and coal mining, 
geology descriptive and applied, lead, limestone, peat, 
uranium and zinc may be taken as examples. The list is, 
of course, confined to the works in the Patent Office, and 
it contains titles of a few books and pamphlets that are 
worthless from a practical point of view, such as “‘ King 
Coal’s Levee” (1820). Institutions should have authority 
to part with works of this kind, so that they might be placed 
in appropriate libraries. The practical utility of the list 
is, however, great, and the price is only 6d. 
Some Jurassic fossils from Borneo have been described 
NO. 1780, VOL. 69] 
by Mr. R. Bullen Newton (Proc. Malacol. Soc., v., October). 
These include a new species of Trigonia (T. Molengraaffi), 
the genus being recorded for the first time from the rocks 
of Borneo. The characters of the fossils indicate that the 
strata belong to the Lower Oolites. 
In some notes on the origin of coral reefs (Amer. Journ. 
Sci., September) Mr. J. Stanley Gardiner remarks that 
while some reefs may possibly owe their existence to the 
subsidence of the land round which they originally formed 
only a fringe, yet the facts collected during recent years 
prove that such a method of formation was rare and ex- 
ceptional. Referring to the Maldive group, he shows that 
a study of the reefs indicates the following stages :—(1) a 
basis of primitive rock cut down by the action of currents, 
&c., and lying at a depth of about 200 fathoms in a sea of 
more than 2000 fathoms; (2) upgrowth of a shoal by means 
of deep-sea corals assisted by other organisms; (3) outward 
extension of the reef by means of detritus; (4) surface reef 
formed by corals, &c. ; (5) land, formed by piling up of sand 
and rubble on the reef; and (6) lagoon, formed partially by 
the more rapid growth of the organisms on the edge of the 
original bank, building up an encircling reef, and partially 
by the solution and erosion of the central parts. 
BIOLOGICAL TREATMENT OF SEWAGE. 
OR some years a very interesting series of experiments 
in connection with the biological method of sewage 
treatment has been carried on by Dr. Dunbar, director of 
the Hygienisches Institut at Hamburg, and by his col- 
leagues. Special attention has been directed to the 
elucidation of the sequence of changes which underlies 
the purification process in contact beds and percolating 
filters. 
The most recent conclusions are given in a paper read 
by Dr. Dunbar at the International Congress of Hygiene 
and Demography at Brussels, and in several papers in the 
Gesundheits-Ingenieur, more especially in one by Messrs. 
Kattein and Liibbert in No. 25 of that journal. Great im- 
portance is attached by the Hamburg workers to the réle 
played by the process of so-called *‘ absorption ’’ which 
takes place when the liquid is in contact with the purify- 
ing medium. It has been found that sterile clinkers have 
the power of withdrawing from solution not only colouring 
matters, but also the highly complex nitrogenous bodies 
found in sewage. 
The exact meaning to be given to the term absorption 
is carefully discussed by Kattein and Liibbert in their paper, 
with copious references to the literature of the subject. It 
is defined as a purely surface action independent of chemical 
attraction, analogous, in fact, to the condensation of 
carbonic acid on glass threads observed by Bunsen. 
The purification of the sewage by the ordinary biological 
methods is considered, in the first place, to be due to the 
““ absorption ’’ by the medium of the putrefactive matters 
in solution, which are afterwards oxidised through the 
intervention of micro-organisms. Without the activity 
of the organisms in presence of oxygen, absorption soon 
ceases. 
The absorptive effect increases with the surface exposed, 
i.e with the fineness of the material. Very considerable 
reduction of impurities can be effected by a contact of a 
few minutes, and the effect practically attains its maximum 
in from four to six hours. 
Besides the destruction of the absorbed organic matter, 
which is due to micro-organisms, some oxidation is effected 
directly by the atmospheric oxygen, which is also absorbed, 
and which is shown to be in a specially active condition, as 
it is capable of instantly oxidising hypochlorites to chlorates, 
and, more remarkable still, of converting dimethyl-aniline 
into methyl-violet. The last change can only be brought 
about in the ordinary way by heating with chlorate, or 
other powerful oxidising agent. 
An interesting example of absorption is seen in the case 
of the percolating filter adopted by Dr. Dunbar. This filter 
is provided with a layer of fine material on the surface, 
about six inches deep. According to Dr. Dunbar, 50 per 
cent. of the purification, apart from nitrification, takes 
place in this six inches. 
