THE AUSTRALIAN ‘NATURALIST. 181 
(from both root-suckers, and seeds) A. obtusata, var, in my 
garden at Leura, and hope to secure examples of 4. Dorothea 
this season. 
Acacia obtusata, Sieb. var, Hamiltont Maiden will be 
found described and figured in Mr. Maiden’s work, The For- 
est Flora of N.S.W., V. 153, plate 131. 
As most or uur members are familiar with the topo- 
graphy of Leura, no difficulty should be experienced by those 
interested in following the boundaries of these Acacias as 
they occur in this locality. 
Both have been found west of Leura, A. Dorothea as 
far as Clarence Siding, and A. obtusata, var, at Mt. Wilson 
(in young bud), by Mr. Maiden in 1896, and recently it was. 
discovered at Bell, in close proximity to the species of which 
it is a variety, A. obtusata, Sieb. The latter plant, though 
well established on the southern tableland, is rare on the: 
Blue Mountains. (Forest Fl., V. 130.) > 
NO?K ON EXHIBIT OF PLATES OF VOLCANIC ERUP- 
TION AT SAVAII, SAMOA, OCT. 1905. 
(By C. B. Fidler, B.A.) 
The photos. exhibited were kindly lent by Rev. Dr. 
Brown. The lava flood covered from 20 to 25 square miles of 
country to a depth, in‘some places, of between 300 and 400 
feet. Two photos show @ portion of the lagoon whicle in a 
fortnight was converted into an iron-bound coast. An inter- 
esting picture shows the four walls of a dwelling surrounded 
by the lava to their full height.. The lava surrounded, but 
did not destroy, the house. The explanation suggested is 
that the gases evolved from the lava formed a protecting 
cushion between the latter and the walls. A similar case is 
given by Kingsley in “‘Madam How and Lady Why,’’ and he 
explains the phenomena in this manner. That large volumes 
of gas are given off by the lava is demonstrated by the fact 
that in the crater at Savaii bubbles rose large enough to send 
waves to the sides. 
In the discussion which followed the reading of this note 
Mr. Sussmilch said that so far as he could see from the photos 
the lava descended slowly, cooling rapidly on the outside as 
it progressed. Any moderate-sized object would readily turn 
aside a sluggish stream of this kind. Slag running from a 
blast furnace can be diverted by a pebble placed in its path. 
(The occlusion of gases in lava and in the rocks produced by 
its solidification, as well as other rocks, is well known. By 
heating fragments of rock in an exhausted flask, the gases 
