200 DESTRUCTION OF POMPEII. 
and finally, he states, " two entire cities, Hercula- 
neum and Pompeii, were buried under showers of 
ashes, while all the people were sitting in the 
theatre." 
Mr. Lyell thinks that there is no evidence to prove 
that any lava flowed from Vesuvius in 79, and that 
the ejected substances which overwhelmed Pompeii 
were lapilli, sand, and fragments of molten lava, as 
when Monte Nuovo was thrown up in 1538. From 
the excavations which have been made, it is certain 
that none of the inhabitants perished in the theatres, 
and that but very few perished at all. 
It appears, from an examination made by Mr. 
Lyell in 1828, that the city of Pompeii was covered 
"with numerous alternations of different horizontal 
beds of tuff and lapilli,* for the most part thin, and 
subdivided into very thin layers. 
The following is a section : 
Fig. 43. 
^ , Ft. In. 
^, Black sparkling sand - - 0 2 
Vegetable mould - - - 3 0 
ilii Brown incoherent tuff - - I 6 
Small scoriae and white lapilli* - 0 3 
Brown earthy tuff - - - 0 9 
Do. with lapilli in layers - 4 0 
^-er of whitish lapilli - - 0 1 
Gray solid tuff - - - 0 3 
Pumice and white lapilli - - 0 3 
The depth of the bed of ashes above the houses 
is variable, but seldom exceeds 12 or 14 feet. Nos. 
3 and 5 of the above strata were filled with small 
prismatic globules. Mr. Scrope saw these formed 
in great numbers in 1822, by rain faUing during a 
volcanic eruption on fine volcanic sand ; and he also 
states that they are produced like hail in the air, by 
th^ mutual attraction of the finest particles of damp 
* Small volcanic cinders, little stones. 
