120 
NATURE 
[SEPTEMBER 25, 1913 
well be calcareous precipitates deposited by algal 
influence. Many of these deposits are similar to those 
mentioned above from British rocks. 
No undoubted remains of calcareous alge have, 
however, yet been recorded from these Belgian rocks. 
It may be of interest, therefore, to mention the recent 
discovery by Prof. Kaisin, of Louvain, of undoubted 
algal remains in the beds overlying the Psammites-de- 
Condroz at Feluy, on the Samme. The form found 
here resembles Ortonella of the Westmorland rocks, 
but the tubes are much finer, and it may turn, out to 
represent a species of Micheldeania. During a recent 
visit to Belgium I had the pleasure of visiting the 
Comblain au Pont beds, in the Feluy section, with 
Prof. Kaisin, and, although these beds have been 
previously classed as Devonian, I agree with him 
that they probably belong to the base of the Car- 
boniferous, and correspond approximately to K of the 
Bristol sequence. In the company of Prof. Dorlodot 
and Dr. Salée, I also visited the chief sections of the 
Visean, and we succeeded in discovering at least three 
horizons at which nodular concretionary structures, 
probably referable to algal growths, occurred. It is 
pretty certain, therefore, that careful microscopic in- 
vestigation of the Belgian rocks will show the 
presence of calcareous algze at more than one horizon. 
One other occurrence of Girvanella may be men- 
tioned from foreign Carboniferous rocks: that is a 
form described by Mr. H. Yabe from the (?) Car- 
boniferous rocks of San-yu-tung and other localities 
in China under the name of G. sinensis.*° 
PERMIAN AND TRIAS. 
In Britain I have met with no reference to the 
occurrence of calcareous algz in rocks of this period, 
but quite recently Mr. Cunnington, of H.M. Geo- 
logical Survey, sent me a few nodules from the base 
of the Permian which resemble very closely frag- 
ments of Spongiostroma from the Carboniferous lime- 
stone, and may be derived from that formation, 
Abroad, masses of limestone, composed almost 
entirely of remains of Diplopora and Gyroporella, 
have long been known from the Muschelkalk and 
lower Keuper beds of the eastern Alps, notably the 
Mendola Dolomite, the Wetten limestone of Bavaria, 
and the Tyrolian Alps—from the Zugspitz to Berchtes- 
gaden. In the Hauptdolomit and from the Fassa 
Dolomite of the north limestone Alps and the stratified 
Schlern dolomite of the southern Tyrol. In the Lom- 
bard Alps the same facies reappears, and Diplopora 
annulata occurs abundantly in the well-known Esino 
limestone above Varenna. 
In 1891 Rothpletz** showed that certain spherical 
bodies in the Triassic beds of St. Cassian, formerly 
regarded as oolitic structures, were in_ reality 
algal growths, and referred them to a new 
genus, Sphcerocodium, on account of their ap- 
parent resemblance to the living form Codium. 
He describes them as encrusting organisms forming 
nodules up to several centimetres in diameter. They 
contribute substantially to the rocks in which they 
occur, and are found especially in the Raiblkalk, the 
Kossenerkalk, and the Plattenkkxalk. 
Jurassic. 
The Mesozoic rocks of Britain contain but few 
examples of marine algal limestones, and important 
occurrence are confined to the Jurassic Rocks. The 
forms met with are limited to two genera, Girvanella 
and Solenopora. 
Tubes of Girvanella occur fairly abundantly in the 
30 H. Yabe, ‘‘ Science Reports of the Tahoku Imp. Univ.,” Japan, 1912. 
31 “ Zeitsch. d. deut. Geol. Ges.,” 189r- 
NO. 2291, VOL. 92] 
British Oolites, especially in the well-known Leck- 
hampton Pisolites, and Mr. Wethered, who has made 
a special study of oolitic structures, appears inclined 
to refer all oolitic structures to organic agency of this 
nature. 
The examples of Solenopora met with in the Great 
Oolite and Coral Rag are of special interest. In both 
cases they attain very much larger dimensions than 
any species yet discovered in the Palzozoic rocks. 
At Chedworth, near Cirencester, I have collected 
masses of Solenopora jurassica, measuring up toa foot 
across, in which the original pink tint is still so con- 
spicuous on freshly fractured surfaces as to give rise 
to the local appellation of ‘* Beetroot Stone,’’ and the 
colour also reminds one of the red algee growing in 
great profusion at the present day in the Gulf of 
Naples. 
It is also recorded from the same horizon by Dr. 
Brown from Malton in Yorkshire, and also, on the 
authority of the late Mr. Fox Strangways, by Prof. 
Rothpletz. (Op. cit.) 
In Yorkshire, however, a form undoubtedly occurs 
at a higher horizon, namely, in the Coral Rag of 
‘the Scarborough district, where it is well known to 
local collectors. Specimens which I have collected 
from this horizon at Yedmandale and Seamer also 
attain a considerable size—up to six inches in their 
longest dimension. : 
The name S. jurassica was given by Prof. Nicholson 
in manuscript to the specimens from Chedworth, and 
was adopted by Dr. Brown in his description of speci- 
mens from both Chedworth and Malton. 
Prof. Rothpletz points out that specimens examined 
by him from Yorkshire differ from the genotype in 
the fact that the cells are typically rounded in cross 
section and by the absence of perforations in the cell- 
walls, and he therefore proposes to separate it as a 
new genus Solenoporella. It seems probable that 
some confusion has arisen between the specimens 
to which Nicholson originally gave the name of 
S. jurassica from the Great Oolite of Chedworth and 
other specimens from a higher horizon—the Coral 
Rag—examined by Dr. Brown and Prof. Rothpletz. 
The former indeed figures a longitudinal section 
from Chedworth (Glos.) and a tangential section from 
Malton (Yorkshire). 
I have collected specimens from both horizons and 
consider that whilst the Chedworth specimen, to which 
the name Solenopora jurassica was originally given, 
represents a species of true Solenopora, showing 
closely packed cells with polygonal outline in tan- 
gential section, the form from the Coral Rag of York- 
shire, with distinct circular outline to the tubes in 
tangential section is specifically, if not generically, 
distinct, and is that described by Rothpletz as Soleno- 
porella. 
If this view be correct we should continue to speak 
of the specimens from the Great Oolite at Chedworth 
as Solenopora jurassica, while those from the Coral 
Rag of Yorkshire must be known as Solenoporella 
sp. Rothpletz. ; = 
Foreign Jurassic. 
It is surprising that records of the occu-rence of 
calcareous algz in foreign Jurassic rocks are at 
present very scarce. 
Quite recently, however, Mr. H. Yabe** has 
described a new species of Solenopora, under the title 
Metasolenopora Rothpletzi, from the Torinosu lime- 
stone Japan. This discovery is of interest, as it 
carries the known occurrence of Solenopora up to the 
base of the Cretaceous, in which formation Litho- 
thamnion appears and thenceforward becomes the 
32 Of. cit, p. 2 
