234 
NATURE 
| Fuly 20, 1871 

genus Ayorria.—Mr. A. G. More continues his Supplement to 
the “Flora Vectensis ;” and the Rev. Jas. M. Crombie his addi- 
tions to the British Lichen-Flora. 
The number for July contains Mr. Ernst’s ‘Jottings from a 
Botanical No:e-book,” and concludes Mr. A. G. More’s ‘* Sup- 
plement to the Flora Vectensis.” Dr. Trimen contributes some 
notes on plants observed in Jersey and Guernsey in April. 
There are several other short papers and notes of special interest 
to British botanists. 
Or the Bidliothégue Universelle et Revue Suisse, one of the 
most valuable of continental periodicals, whether we consider the 
quality of its original articles, or the admirable extracts of scien- 
tific memoirs which it contains, we have just received the part 
published on May 15, which forms the commencement of anew 
volume. The first and most important of the three papers con- 
tained in it is on the action of magnetism on gases traversed by 
electrical discharges, by MM. A. de la Rive and E. Sarasin, in 
which the authors describe a long series of experiments made by 
them, leading to the following conclusions :—1. The action of 
magnetism exerted only upon a portion of an electric jet travers- 
ing a rarefied gas, causes an augmentation of density in this por- 
tion. 2. This action exerted upon an electric jet placed 
equatorially between the poles of an electro-magnet, produces in 
the rarefied gas an augmentation of resistance proportional to the 
conductivity of the gas itself. 3. On the contrary, it causes a 
corresponding diminution of resistance, when the jet is directed 
axially between the two magnetic poles. 4. When the action of 
the magnetism is to impress a continuous movement of rotation | 
upon the electric jet, it has no influence upon the conductivity if 
the rotation be in a plane perpendicular to the axis of the iron 
cylinder detaining the rotation, and diminishes it considerably if 
the rotation takes place so that the jet describes a cylinder round 
the axis. 5. These effects do not seem to be due to variations of 
density, but to perturbations in the arrangement of the particles 
of the rarefied gas —A second paper is an excellent abstract and 
discussion by M. Emile Gautier, of the observations of solar pro- 
tuberances, made at Rome by Prof. Respishi; and the third 
consists of an account of geological, meteorological, and archzeo- 
logical explorations made in the province of Constantine (Al- 
geria), by M. Tissot. 
THE first part of the twenty-third volume of the Zeitschrift der 
deutschen geologischen Gesellschaft, containing the proceedings of 
that society for the months of November and December 1870, 
and January $71, includes one paper which will be of especial 
interest to British geologists, namely, ‘‘ Some Geological Sketches 
from the East Coast of Scotland,” by Prof. F. Zirkel, extending 
over 124 pages of text, illustrated with four plates. 
the complicated geology of the islands of Arran, Mull, Iona, 
Staffa, and Skye is discussed in considerable detail, and the 
author winds up with a description of the east and west section 
of the north of Scotland. Another long paper is the first part of 
a geological description of the annular mountain of Santorin, by 
M. K. von Fritsch. —M. C. Struckmann describes the Pveroceras | 
beds of the Kimmeridge formation at Ahlem, near Hanover, which 
he divides into three series (upper, middle, and lower), indicating 
the characteristic fossils of each deposit. M. R, Richter pub- 
lishes a fourth notice on the Thuringian slates, for which he 
claims an Upper Silurian age, an opinion here supported chiefly 
on the evidence of Graptoliies. The author discusses the affini- 
ties of the Graptolitidae, and adopts an opinion expressed by 
Leuckart (MS.) that this group is to be regarded as nearly allied 
to the Bryozoa. The author describes a new genus, 777plograp- 
tus, the chief character of which is that the canal has three ver- 
tical rows of alternating cells, of which the type is Z: werestarum 
(Richt.), and also as new species Diflograptus pennatulus and 
Monagraptus crenatus. These and some other species are figured 
in the plate accompanying the memoir. A new species of Vauti- 
In this paper | 

Jus (N. veles) is also described and figured in this paper (p. 243). | 
From M. Emanuel Kayser we find a notice of the occurrence of 
Rhynchonella pugnus with traces of colour in the limestone of 
the Eifel (Devonian), to which is appended a tabular list of those 
fossil shells on which traces of colouration have been observed. 


SOCIETIES AND ACADEMIES 
LonboNn 
Geological Society, June 21.—Joseph Prestwich, F.R.S., 
inthe chair.—R. J. Watson, W. T. Scarth, Gen. A. C. Bentinck, 
and John Brooke were elected Fellows of the Society.—‘‘ On 
some supposed Vegetable Fossils,” by William Carruthers, 


F.R.S. In this paper the author desired to record certain 
examples of objects which had been regarded, erroneously, as 
vegetable fossils. The specimens to which he specially alluded 
were as follows :—Supposed fruits on which Geinitz founded the 

genus Guilielmites, namely, Carpol:tes umbonatus Sternb., and — 
Guiliclmites permianus Gein., which the author regarded as the — 
result of the presence of fluid or gaseous matter in the rock when 
in a plastic state ; some roundish bodies, which, when occurring 
in the Stonesfield slate, have been regarded as fossil fruits, but 
which the author considered to be the ova of reptiles, and of 
which he described two new forms ; and the flat, horny pen of a 
Cuttlefish from the Purbeck of Dorsetshire, described by the 
author as Zvudopsis Brodie, sp.n. Mr. Seeley remarked on 
the compressed spheroids found in so many rocks, that there was 
a difficulty in acceptirg the view of their originating in fluid 
vesicles, though he was unable to suggest any other theory by 
which to account for them. He observed that the eggs from the 
Stone-field slate closely resemble those of birds, and that it was 
of the highest interest to find such eggs in strata containing so 
many remains of ornithosaurian forms, such as Aamphorhynchus 
and Pterodacty/us, of which genus probably these were the eggs. 
Prof. Rupert Jones fully recognised the ingenious explanation of 
the bubble-formed limited slickensides, that looked so much like 
possible fossil fruits, and Mr. Carruthers’s masterly treatment of 
the other specimens. But he wished that the author would take 
up the subject exhaustively, and define the nature of other 
supposed vegetable fossils, such as the so-called fucoids, 
Paleochorda, Paleophyton, Oldhamia, &c, many, if not all, of 
which Prof. Jones thought to be due to galleries and other tracks 
made by Crustaceans. Prof. Ramsay had known many instances 
of such blunders as those poinred out, made, not by experienced 
geologists, but by those unacquamted with the science. Though 
he had never regarded the flattened spheroids as fossils, he was 
unable to account for their presence in the clay-beds of different 
ages. Mr. Hulke inquired whether Mr. Carruthers considered 
the limited slickensides common in the Kimmeridge shales as 
due to gaseous origin. He remarked on the rarity of Ptero- 
dactylian remains as compared with those of other Saurians in 
the Wealden beds, in which the presumed eggs of Pterodactyls 
were found. Mr. Seeley did not regard the Wealden egg as 
being that of a Pterodactyle. Mr. Carruthers, in reply, re- 
marked that the local slickensides mentioned by Mr. Hulke 
differed in character from those to which he had referred.— 
| ** Notes on the Geology of part of the County of Donegal,” by 
| A. H. Green, F.G.S. 
| geological structure of che country in the neighbourhood of the 
In this paper the author described the 
Errigal Mountain, with the view of demonstrating the occurrence 
in this district of an inter-stratification with mica-schist of 
beds of rock, which can hardly be distinguished from granite, 
the very gradual passage from alternations of granitic gneiss and 
mica-schist into granite alone, and the marked traces of bedding 
and other signs of stratification that appear in the granite, to 
which the author ascribed a metamorphic origin. He also 
noticed the marks of ice-action observed by him in this region, 
and referred especially to some remarkable fluted bosses of 
quartzite, and to the formation of some small lakes by the scoop- 
ing action of ice. Mr, Forbes stated that none of the facts of 
this communication were new, but he dissented altogether from 
the conclusions arrived at by the author in regarding these rocks 
as originally of sedimentary origin, and for the following reasons ; 
(1) That this district has been studied in detail by Mr. Scott and 
Prof. Haughton, who declare the rock to be undoubtedly intru- 
sive, as it not only sends out veins into the neighbouring strata, 
but also encloses fragments of the rocks through which it has 
broken. (2) Because the author starts from the idea that if such 
rocks are found to lie conformably on beds of undoubted sedi- 
mentary origin, it is a proof of their being themselves sedimentary 
or stratified,—a conclusion which is totally unwarranted, since 
there are innumerable in-tances, not only of beds of lava or other 
igneous rocks being conformable to fossiliferous strata, but of 
their also being found intercalared with such beds even for con- 
siderable distances. (3) The strata, so far from being proved by 
him to be of truly sedimentary origin, are of a most questionable 
origin, since they are neither in themselves fossiliferous, nor can 
they be correlated with any containing fossils as proofs of true’ 
sedimentary deposition ; and the description of his section is 
sufficient to show this ; for although it looks well on paper on a 
scale of three feet to the mile, the author has so little conhidence 
in it that he is not ever certain as to which is the tep or bottom 
of the section on which so much generalisation is based. (4) 
