NovEMBER 20, 1913] 
Output in Millions of Tons. 
1865 1912 
South Staffs... Fe PLO a 7k 
Leicester Reet Kid ERGs pa 22 
Warwick ron ae  Aaedarey 43 
SAlOper. osk a5) eas |, ler, x 
Total, ~ .... cot TRE Nae 153 
Dr. E. A. Newell Arber gave a preliminary note 
on the fossil floras of the South Staffordshire Coal- 
field, which include both petrifications and impres- 
sions, and expressed the hope that in course of time 
it will be possible to trace the floras systematically 
from the lowest to the highest beds of the Coal 
Measures of this coalfield. 
In a paper on the correlation of the Leicestershire 
Coalfield, Mr. R. D. Vernon stated that it had been 
found impossible to use either the sandstones or the 
seams of coal in the correlation even of the eastern 
and western portions of the Leicestershire Coalfield 
itself, and that fossil plants had also proved of rela- 
tively little value, and the fresh-water lamellibranchiata 
were equally unsatisfactory. For these reasons a 
search was made for marine beds. The thickest 
marine bed occurs about 260 yards above the Moira 
Main coal, and its outcrop has been mapped on the 
it is comparable with the Gin Mine marine bed of 
that in stratigraphical position and in faunal contents 
it is comparable with the Gine Mine marine bed of 
North Staffs, the Mansfield marine bed of the York- 
shire and Nottinghamshire field, and the Pennystone 
Ironstone marine bed of Coalbrookdale, and therefore 
serves as a means of correlating the Measures of 
Leicestershire with those of neighbouring areas. 
On systems of folding in the Palazozoic and newer 
rocks, by G. Barrow. The author is of opinion that 
many so-called systems of folding are due to series of 
resisting masses with parallel margins, and cites as 
examples the great lenticular masses of thermally 
altered rocks of the Highlands. 
In a paper on the Harlow Boulder Clay and its 
place in the glacial sequence of eastern England, Dr. 
A. Irving dealt with the sequence of the various 
deposits of Pleistocene age in the eastern counties of 
England. 
The discovery of Lower Carboniferous Grits at Lye, 
in South Staffordshire, was recorded by Mr. W. W. 
King and Mr. W. J. Lewis. 
Mr. E. A. Walford read a paper on some of the 
basement beds of the Great Oolite and the Crinoid 
beds, and suggested the following subdivision of the 
Great Oolite :— 
Uprer Great Ootire.—(1) Terebratula maxillata 
beds; (2) Calcaire a Echinodermes. 
Lower Great OoritE.—(1) Striped Limestones; (2) 
Rhynchonella concinna beds; (3) Stonesfield Slate. 
Sus-BaTHoNIAN.—(1) Striped Limestone and Crinoid 
beds; (2) Nezeran series; (3) Striped Crinoid Marls; 
(4) Chipping Norton Limestones. 
_ Mr. A. R. Horwood directed attention to the value 
of a knowledge of the rock soil distribution of plants 
in tracing geological boundaries, and pointed out the 
consequent importance of the new ccological surveys 
to the geologist. 
The geology of the district between Abereiddy Bay 
and Pen Caer, Pembrokeshire, formed the subject of 
a paper presented by Dr. A. H. Cox and Prof. O. T. 
Jones, in which it was shown that not only Llandeilo 
and Bala rocks, as previously supposed, but Arenig 
and even Cambrian rocks form large areas on the 
coast. The authors propose to map the area in detail. 
“The Relation of the Rhiwlas and Bala Limestones 
at Bala,” by Dr. Gertrude L. Elles. The Rhiwlas 
NO. 2299, VOL. 92| 
NATURE 
359 
Limestone is an impersistent limestone at the base of 
the Hirnant Series, and is found only in the northern 
part of the area. The Bala Limestone is not developed 
as a calcareous bed in the northern part of the area. The 
true relation of these horizons to each other is seen 
at Gelli Grin, where the Bala Limestone at its maxi- 
mum thickness is overlain by light-coloured, pasty 
mudstones, containing a typical Rhiwlas Limestone 
fauna. 
The work of excavation of critical sections in th» 
Cambrian rocks of Shropshire has been continued, 
and has furnished paleontological proofs of the pro- 
longation of the Lower and Middle Cambrian rocks 
of Comley into the Cwms area to the south, and a 
description of excavations Nos. 53, 54, 55, and 56 
formed the subject-matter of a communication by 
Mr. E. S. Cobbold, who has been carrying on the 
work. 
Dr. A. Irving furnished a contribution to the much- 
discussed question of ‘* Flint and its Genesis.”’ Silicifi- 
cation of calcareous fossils can be understood as a 
‘*mass-reaction’’ of the allxaline silicates in the pre- 
sence of a large excess of water :— 
nH,0+CaCO,+K,Si0,=K.CO, + Ca(OH), + 
(aissolved) 
SiO, +(n—1)H,O. 
(precipitated) 
Plant petrifactions in chert and their bearing on 
the origin of fresh-water cherts was discussed by 
Dr. Marie C. Stopes, who directed attention to the 
recent ‘“‘sapropel’’ observed by Potonie, and the like- 
ness it has to the débris in certain cherts from Asia 
Minor, and concluded that the chert may be taken 
as practically pure petrified ‘‘ sapronel.”’ 
Dr. Vaughan Cornish directed attention to the 
conditions which govern the transport and accumu- 
lation of detritus by wind and water. 
In a communication on the shelly and graptolitic 
faunas of the British Ordovician, Dr. Gertrude L. 
Elles showed that there are two main types of 
“shelly”? faunas of Ordovician age in the British 
Isles, and that each of these can be further sub- 
divided into a number of subfaunas, which can be 
correlated by reference to associated graptolite-bear- 
ing beds. The main shelly types were described as 
(a) Asaphid-Trinucleid-Calymenid fauna; (b) Cheirurid- 
Lichad-Encrinurid fauna. It was suggested that 
fauna (b) is an exotic fauna, possibly southern in 
origin, which migrated into the British area. Becom- 
ing early established in south Scotland, it soon spread 
west into Ireland, but did not dominate the whole 
British area until Ashgillian times. Correlation tables 
were given showing the relations of the various faunas 
of the groups (a) and (b) to the graptolite zones of 
the series. , 
“A First Revision of the British Ordovician 
Brachiopoda, by Clara E. Sylvester. The author gave 
a summary of the present stage of her researches 
among the British Ordovician Brachiopoda, and pre- 
sented a table of the known species, with their range 
and geological and geographical distribution. The 
species in each genus were grouped around well- 
known forms selected as types. 
Mr. W. D. Matthew gave a paper on discoveries in 
the American Eocene. 
In further notes on Paleoxyris and other allied 
fossils, with special reference to some new features 
found in Vetacapsula, Mr. L. Moysey directed atten- 
tion to several features which had been found in cer- 
tain new material collected since the publication of 
his paper in the Quart. Journ. Geol. Soc., 
vol. Ixvi., Igto. 
Mr. Frank Raw gave a paper on the occurrence 
of a wind-worn rock surface at Lilleshall Hill, Salop. 
