Geology of Monte Somma and Vesuvius. 239 
5. " The Geology of Monte Somma and Vesuvius, being a Study- 
in Yulcanology." By H. J. Johnston-Lavis, Esq., E.G.S. 
The author, after referring to the vast amount of literature which 
has appeared dealing with the same subject, stated that his object 
was to lay before the Society the results of his personal observations. 
The external form and general features of Monte Somma having 
been described, the origin of the present condition of the volcano was 
discussed in some detail, and the geological structure of the moun- 
tain and of the surrounding plain, as revealed by well-sections, was 
carefully considered. 
As the result of his observations, the author believes that he is 
able to define eight successive phases in the history of the volcano ; 
and the events which took place during these several periods, with 
the products of the eruption during each, were discussed in detail. 
The earliest certainly recognized phase in the history of the 
mountain was distinguished by chronic activity, exhibited in out- 
flows of lava and the ejection of scoria and ash. Possibly, however, 
a still earlier and paroxysmal stage is indicated by some of the phe- 
nomena described. 
Phase II. was a period of inactivity and denudation, which was 
brought to a close by the violent paroxysms of Phase III., followed 
by the chronic activity of Phase IV. Phase Y. marks the return of 
a period of inactivity and denudation, which was again followed by 
the paroxysms of Phase YI. and the less violent outbursts of 
Phase YIL, the last subsiding into the chronic activity which is 
the characteristic of Phase YIIL, the modern period of the history 
of the volcano. 
The products of each of these periods of eruption were described 
in great detail. 
The eruptive phenomena which are illustrated by these studies 
of Somma and Vesuvius were then considered, together with the 
nature and result of the denudation which alternated with eruptive 
action in originating the present form of the mountain. 
The paper concluded with a statement of fifty propositions on the 
subject of vulcanology which appear to the author to be established 
by the studies detailed in the paper. 
6. " Xote on ' Cone-in-Cone ' Structure." By John Young, Esq., 
E.G.S. 
This note was written with the object of calling the attention of 
the Geological Society to some very fine and remarkably interesting 
examples of the " Cone-in-Cone " structure. 
The author, after referring to the views of previous authors on 
the origin of this structure, proceeded to describe the interesting 
examples of it which occur in the coalfields of Ayrshire and Ren- 
frewshire. He pointed out that the structure is generally exhibited 
in bands overlying beds of fossils. 
7. "A Geological Sketch of Quidong. Manaro, Australia."' Bv 
Alfred Morris, Esq., C.E., F.G.S. 
This district is situated about 250 miles S.S.E. from Sydney. The 
