I. GEOLOGY. 707 



3273. The Great Crater of Vesuvius. Photograph, show- 

 ing the interior after the eruption of April 1872. 



Robert James Mann, M.D. 



This photograph was taken by Mr. J. M. Black from the gap in the broken 

 edge of the rim. The top of the great rent, extending north and south through 

 one side of the cone into the Atreo del Cavallo, is shown on the further side of 

 the crater between the rounded and pointed eminences. 



3274. Pour Sketches representing a Volcanic Eruption, 



to illustrate the form. 



Mineralogical and Geological Cabinet of the School of 

 Industry, Cassel (Dr. H. Mohl). 



3275. Four Views of Crater Eruptions. 



Mineralogical and Geological Cabinet of the School of 

 Industry, Cassel (Dr. H. Mohl). 



The drawings are used as wall maps to illustrate geological lectures. For 

 more information, v. Papers XL, XIII. 



3276. Photographic Views (2) of Mount Sorrel granite 

 quarries, Charnwood Forest, Leicestershire, by Messrs. T. and J. 

 Spencer. W. J. Harrison, Town Museum, Leicester. 



This rock is a tough hornblendic granite, largely used for revatt setts, 

 kerbs, &c. 



3277. Photographs of the slates and syenites of Charnwood 

 Forest, and of a column of the hard rocks of Leicestershire erected 

 in the grounds of the Leicester Town Museum. 



W. J. Harrison, Town Museum, Leicester. 



These rocks are coloured as Cambrian on the maps of the Geological Survey, 

 but they have yielded no fossils, and the evidence of superposition is not clear, 

 as the oldest rocks near are of Mountain Limestone. The views are by Messrs. 

 J. Burton and Sons. 



3278. Rock Sections. Series prepared for microscopical 

 examination. James How fy Co. 



3281. Belief Map of the Habichtswald, near Cassel, 

 province Hesse-Nassau ; petrographically coloured. 



Friedrich Sievers, Wehlheiden, near Cassel. 



Constructed from the maps of the former electorate of Hesse, the level lines 

 in which were taken at a distance of 60 Prussian feet apart, so that the surface 

 of the North Sea is represented by 0. 



The distribution of the rocks is shown in colours according to the observa- 

 tions of Dr. Mohl and the exhibitor, as follows : 



Carmine - - the lower group of the " Bunter " sand- 



stone. 



Keddish yellow - - the upper group of the same. 



Blue - " Muschelkalk." 



Light-greenish grey - clay and sand with lignite. 



Dark-greenish grey - marine sand rich in fossils, and septarium 



clay (Upper Oligocene). 

 White - - alluvium. 



Black - basalt. 



Brown - - basalt conglomerate. 



Yy2 



