Intelligence and Miscellaneous Articles. 389 



arctic severity ; whilst the presence of remains of the Hippopotamus 

 associated with the same group of animals would indicate a hot 

 summer, such as prevails on the lower Yolga. 



May 24, 1871. — Prof. John Morris, Yice-President, in the Chair. 

 The following communications were read : — 



1. " On the principal Features of the Stratigraphical Distribution 

 of the British Fossil Lamellibranchiata." By J. Logan Lobley, Esq., 

 F.G.S. 



In this paper the author showed, by means of diagrammatic 

 tables, what appears to be the present state of our knowledge of the 

 general stratigraphical distribution of the fossil Lamellibranchiata 

 in Britain. As a class, the Lamellibranchs are sparingly repre- 

 sented in the Lower, and more numerously in the Upper Silurian 

 group, and fall off again in the Devonian ; they greatly increase in 

 number in the Carboniferous, become scanty in the Permian and 

 Trias, and attain their maximum development in the Jurassic rocks. 

 They are also largely represented in the Cretaceous and Tertiary 

 series. The stratigraphical distribution of the two great subordinate 

 groups, the Siphonida and the Asiphonida, corresponds generally 

 with that of the class ; the Siphonida predominate over the Asipho- 

 nida in Tertiary formations, whilst the reverse is the case from the 

 Cretaceous series downwards. Nearly all the families of Lamelli- 

 branchs are represented in the Jurassic and Carboniferous rocks, 

 and in the former very largely. The author remarked especially on 

 the great development of the Aviculidse in Carboniferous times. 



2. " Geological Observations on British Guiana." By James G. 

 Sawkins, Esq., F.G.S. 



In this paper the author gave a general account of his explora- 

 tions of the geology of British Guiana when engaged in making the 

 Geological Survey of that colony. He described the rocks met with 

 during excursions in the Pomeroon district, along the course of the 

 Cuyuni and Mazuruni rivers, on the Demerara river, on the Essequibo 

 and its tributaries, on the Rupununi river, and among the southern 

 mountains. The rocks exposed consist of granites and metamorphic 

 rocks, overlain by a sandstone, which forms high mountains in the 

 middle part of the colony, and is regarded by the author as probably 

 identical, or nearly identical, with the sandstone stretching through 

 Venezuela and Brazil, and observed by Mr. Darwin in Patagonia. 



L. Intelligence and Miscellaneous Articles. 



ON THE TRANSMISSION OF ELECTRICITY IN LIQUIDS. 

 ABSTRACT OF A PAPER BY DR. D. MACALUSO*. 



TN the first part of this paper the author describes an experimental 

 -*■ investigation of the changes in the resistance opposed by a liquid, 

 relatively to the variations of its transverse section, when this section 

 is greater than the surface of the electrodes immersed in the liquid. 

 * From the Giornale di Scienze Naturali ed Economiche, vol. vii. Pa- 

 lermo, 1871. Communicated by R. Gill, Esq. 



