Geological Society of London. oV9 
6. “Description of a new Genus of Madreporaria from the Sutton 
‘Stone of South Wales.” By Robert F. Tomes, Esq., F.G.S. 
In the Quarterly Journal for 1885 is a detailed description of a 
coral from the Sutton Stone named Astrocenia gibbosa. ‘This speci- 
men is not the type of the species, and a re-examination of it by 
the author has proved that it is not an Astrocenia. Two other 
specimens have also been examined, and as a result of examination 
of the three the author is enabled to found a new genus Siyloseris, 
of which a diagnosis is given, and the specific name gibbosa is 
retained for this, the only known species. The genus will take its 
‘place near Clausastrea, from which it differs by possessing a well 
developed columella and increasing by both fissiparity and gem- 
mation. 
7. “Study of the Dykes of Hope, Idaho.” By Herbert R. Wood, 
Esq. Communicated by the President. 
In this paper a description of the geographical distribution and 
‘characters of acid and basic dykes traversing slates and quartzites 
along the northern shore of Lake Pend’Oreille, Idaho, is accompanied 
by notes on the glaciation of the area. A brief description of the 
microscopic features of the igneous rocks is appended. 
8. “The Rise and Fall of Lake Tanganyika.” By Dr. Robert 
Sieger. Communicated by the President. 
The author refers to Mr. Carson’s paper on the same subject in the 
Society’s Journal for 1892. He himself believes the oscillation of 
level to be analogous to variations reported as occurring in other 
African Jakes, and to be due to climatic change. He brings forward: 
evidence in favour of the coincidence of change of level and climatic 
change, but does not believe that his views are by any means con- 
tradictory to those of Mr. Carson, for the phenomena may be 
explained by a combination of the influences of climate with those 
-of mechanical agencies. 
9. “On Cheilostomatous Bryozoa from the Middle Lias.” By 
Edwin A. Walford, Esq., F.G.S. 
The author describes some forms of bryozoa from the spinatus- 
zone of the Middle Lias near Banbury, some of which had previously 
been classed with the Cyclostomata. The new material not only 
shows the opercular aperture but the opercula in situ, together with 
appendages and supra-oral ovicells characteristic of the Cheilo- 
stomata. In addition he has also found giant cells (cistern cells) 
of form quite dissimilar from the ordinary zocecia and probably 
reproductive. He cites M. Jules Haime as having described in his 
magnificent monograph somewhat similar cells from the Inferior 
“Oolite ; and in the Oxfordshire Great Oolite Bryozoa Mr. Walford 
has found cistern-cells like the Lias species on some colonies like 
Diastopore. He contends that it is merely the acquisition of very 
well-preserved material which is needed to show the necessity of 
removal of many such species to the Cheilostomata. The name 
Cisternophora is suggested for the genus, of which several forms 
-are described. 
The next Ordinary Meeting of the Society will be held on 
Wednesday, November 8th, 1893. 
