Mr. E. Hull on the Distribution of Sedimentary Strata. 333 



hot water, — and particularly the upheaval of the ground at Torre del 

 Greco to a height of 1*12 metre above the sea-level, are mentioned 

 in this communication. 



2. " On the Recent Eruption of Vesuvius." By M. Pierre de 

 Tchihatcheff. 



M. Tchihatcheff' s observations were made at Torre del Greco and 

 Naples from December 8th to 25th. Near Torre del Greco several 

 small craters (9-12) have been formed close to each other in an 

 E.N.E.-W.S.W. line, at a distance of about 600 metres E.S.E. of the 

 crater of 1794, and either on a prolongation of the old fissure or on 

 one parallel. The phenomena mentioned by Signor Palmieri were 

 also described byM. Tchihatcheff in detail. 



3. " On Isodiametric Lines as means of representing the Dis- 

 tribution of Sedimentary (clay and sandy, Strata) as distinguished 

 from Calcareous Strata, with especial reference to the Carboniferous 

 Rocks of Britain." By E. Hull, Esq., B.A., F.G.S. 



The author, in the first place, made a comparison of argillaceo- 

 arenaceous with calcareous deposits, as to their distribution, both in 

 modern and in ancient seas, and stated that he objected to calcareous 

 strata being regarded as sediments, in the strict sense of the word. 

 After noticing the distribution of sediments in the Caribbean Sea, he 

 referred to the relative distribution of limestones as compared with 

 shales and sandstones in the Oolitic formations (comparing those of 

 Yorkshire with those of Oxfordshire), in the Permian strata of Eng- 

 land, and in the Lower Carboniferous strata of Belgium and West- 

 phalia. After some observations on the nature of calcareous deposits, 

 and on the contemporaneity of certain groups of deposits, dependent 

 on the oscillatory movements of land and sea, the author described 

 his plan of showing on maps the relative thicknesses of the two classes 

 of strata under notice, by means of isodiametric or isometric lines. 



Mr. Hull then proceeded to indicate the application of the isodia- 

 metric system of lines to the Carboniferous strata of the midland 

 counties and north of England ; showing that there is a south-east- 

 erly attenuation of the argillo-arenaceous strata, and a north-westerly 

 attenuation of the calcareous strata. The existence, in the Carbo- 

 niferous Period, of a barrier of land crossing the British area, imme- 

 diately to the north of lat. 52°, was insisted upon ; and, although 

 this barrier was probably broken through (in South Warwickshire) 

 in the latter portion of that period, yet it divided, in the author's 

 opinion, the coal-area into a north and a south portion, the latter 

 having a very different set of directions in the attenuation of its 

 strata — the shales and sandstones thinning out eastward, the lime- 

 stones in the contrary direction. 



In conclusion, the author stated that, in his opinion, the source of 

 the Carboniferous sediments was in the ancient North Atlantic Con- 

 tinent, for the existence of which Lyell, Godwin-Austen, and others 

 have argued ; and he inferred that the shores of this Atlantis, com- 

 posed principally of granitoid or metamorphic rocks, were washed on 

 the west side by a current running S. W., which drifted the sediment 

 in that direction, and on the other by a current running S.E., which 

 carried sediment over the submerged British area. 



