Jounston-Lavis—The Eruption of Vesuvius in April, 1906. 169 
these two dust-bands at the two localities just referred to as the equivalents of 
the two dust-beds to the west of the volcano, and, in fact, they can be traced as 
those equivalents. These sections, however, are types that I chose amongst a 
great number of others that I examined, which showed that the red or cocoa- 
coloured dust was, in fact, the more comminuted equivalent of the showers of 
red-brown accessory ejecta (C.) of the sections between Ottajano and S. Casili. 
It would, perhaps, have been more correct, therefore, to include them in that 
division shown in the diagram of the sections Purgatorio and San Patrizio. 
Punra pe~L Nasonge, Montse-Somma. (Plate XX1.) 
(a) 0:05 m. roundish, brownish-black scoria-lapilli, almost wholly essential 
scoria. 
(6) 0°12 m. black scoria-lapill.  Hssential ejecta. 
(c) 0°40 m. chocolate-coloured lapilli, banded, coarser, and finer. Accessory 
ejecta. 
(d) 0:10 m. grey dust (after the 13th April). Accessory ejecta, 
ATRIO DEL CavaLio between the cone and the Colle Umberto. 
(a, 6, and c') 0:15 m. cocoa-coloured, pisolitic dust, with lapilli more to the 
bottom. ‘These lapilli, attaining the size of a hen’s egg or larger, were 
chiefly accessory ejecta, consisting of old cone components, and rarely a 
piece of scoria with sufficient of the characters of essential ejecta. 
(c?) 0.15 m. cocoa-coloured dust. Accessory ejecta. 
(d) 0:15 m. grey, pisolitic dust. Accessory ejecta (after April 13th). 
CaNCELLO DI Cook, on the Salvatore ridge. 
(a, 6) 1 em. black sand, which could be distinguished as consisting of two 
layers. LHssential ejecta ? 
(c') 0°09 m. of grey dust. Essential ejecta? 
(c) 0:05 m. of cocoa-coloured dust. Accessory ejecta. 
(d) 0:05 ? whitish-grey dust, much drifted by the wind, and, therefore, of a 
variable and uncertain thickness. Accessory ejecta (after April 13th). 
ERrEmO, close to the Observatory, on a well-sheltered, flat roof. 
(a and 5) 0-01 m. of coarse sand or small lapilli, the lower half more compact, 
the top looser. Lssential ejecta ? 
(c) 0°10 m. grey pisolitic dust. Lssential ejecta. 
(c’) 0-13 m. stratified cocoa-coloured dust. Accessory ejecta. 
(Z7) 0:3 m. grey dust. Accessory ejecta (after April 13th). 
* I have some doubt whether the bottom black sand is not the same as that which fell in Naples in 
the first days of the eruption, 
