108 
NOTE DESCRIPTIVE OF A STEREOGRAM OF THE 
MOUNT LOFTY RANGES, SOUTH AUSTRALIA. 
By W. N. Benson, B.Sc. 
[Read August 10, 1911.] 
Puates XX, anp XXI. 
In a previous paper a short outline was given of the 
physiography of the Mount Lofty Ranges as it appeared to. 
the writer from observations made during 1908. 
Recently a stereogram has been constructed for the 
Sydney University to illustrate the features on which his con- 
clusions were based. A brief description of this model may 
not be out of place here. The information on which it was 
modelled was obtained from the official map of south-eastern 
South Australia and the topographic map of the vicinity of 
Adelaide. Trigonometrically-determined heights are sadly 
few in number. The general relief of the area between Noar- 
lunga, Angaston, and Murray Bridge, and in the Inman 
Valley is based on the writer’s own sketches and aneroid 
readings. A topographic map of Mount Barker district 
published in the daily Press during the military mancuyres 
of 1908 was also of service. The modelling of the area about 
Mount Compass is based on Mr. Howchin’s map and descrip- 
tions (2) and additional information kindly supplied by him. 
Owing to the writer’s non-acquaintance with areas out- 
side these limits the model may be subject to some modifica- 
tion in those parts, and indeed owing to the smallness of 
scale no more than a very rough accuracy has been attempted 
throughout. 
The small inset model illustrates the main tectonic 
features. As these are being investigated in detail by Mr. 
Howchin a very brief description will here suflice. 
The main portion of the Mount Lofty Ranges, stretch- 
ing from beyond Angaston to Cape Jervis and extending 
into Kangaroo Island, is a peneplain. The main drainage, 
before uplift, was in mature valleys running in an approxi- 
mately meridional direction.) On the peneplain surface 
were residuals of a higher level, monadnocks, such as Mounts 
(1) Trans. Roy. Soc., S.A., 1909, p. 107. 
(2) Trans. Roy. Soc., S.A., 1910, pp. 231-47 and pls. xxxi. to- 

xlr. 
(3) W. Howchin, Geography of South Australia, p. 124. 

