TRANSACTIONS OF SECTION O. 361 
Practically no folding movements are known among the Tertiary rocks of 
Victoria, while plateau movements, generally of elevation, sometimes of depres- 
sion and accompanied by faulting, are widespread. Near Omeo and Mansfield, 
where faulting has been demonstrated or inferred, the highly alkaline types of 
nepheline-phonolite are developed, but the widespread plateau movements in 
Victoria are more specially associated with the occurrence of the normal basalts. 
The alkali trachytes and allied rocks are intercalated between an older and a 
newer basalt series, are developed only sporadically at certain centres, and as at 
Macedon are closely associated in the field with the newer basalts as rocks of 
slightly greater antiquity but belonging to the same volcanic period. 
References to Literature. 
(1) Howrrr, A. W. ‘Rep. Min. Dept. Vict.,’ September 1890. ‘ Rep. Min. 
Dept. Vict..’ March 1890. ‘ Trans. R. Soc. Vict.,” vol. xx. 1884. 
(2) Skrats, EK. W. Aust. Assoc. for Adv. of Science. Presidential Address 
to Section C, Brisbane, 1909. Aust. Assoc. for Ady. of Science, Sydney, 
1911. 
(8) Grirrirm Tayror, T. ‘Com. Bureau of Meteorology,’ Bulletin No. 8, 
1911. 
(4) Fenner, C. ‘Proc. Roy. Soc. of Vict.,’ vol. xxv. N.S., 1913. 
(5) Grecory, J. W. ‘ Proc. Roy. Soc. of Vict.,’ vol. xxv. N.S., 1901. 
Sxeats, EH. W., and Summers, H. 8. ‘Geol. Surv. of Vict.’ Bulletin 
No. 24, 1912. 
(6) Summers, H. 8. Aust. Assoc. for Ady. of Science, Sydney, 1911. 
Dennant, J. Aust. Assoc. for Adv. of Science, Adelaide, 1893. 
Hoee, E. ‘Proc. Roy. Soc. Vict.,’ vol. xii. N.S., 1899. 
6. On the Origin and Relationship of the Victorian Kainozoic Alkali 
Rocks. By H. 8. Summers, D.Sc. 
Alkali rocks of Kainozoic age occur in Victoria in the Macedon District, near 
Coleraine and Carapook in the Western District, and in the neighbourhood of 
Omeo and Mansfield in North-Eastern Victoria. Ejected blocks from the vol- 
canoes near Camperdown have been described as essexite, and a similar type, 
also probably ejected, has been found near Kyneton. With the exception of 
the occurrences of Omeo and Mansfield all these alkali rocks are closely associated 
with the Upper Kainozoic calcic basalts, and the field relations are such that 
there is little doubt that the alkali rocks and the basalts are genetically related. 
Numerous analyses (mainly unpublished) have been made of Victorian basalts, 
and these show that they are fairly normal in composition, and consequently 
should belong to Harker’s Calcic or Pacific Branch of Igneous rocks, whereas the 
sdlvsbergites, trachytes, &c., of Macedon, the phonolites of Omeo and_Mansfield, 
the essexites (?) of Camperdown and Kyneton, and the trachytes and anortho- 
clase-basalts of the Coleraine area must be placed in the Alkali or Atlantic 
Branch. 
It follows then that the evidence of the Victorian Kainozoic rocks does not 
support Harker’s generalisation on Petrographic Regions. 
A number of first-class analyses has been made of the principal types of the 
Macedon series, and variation diagrams based on these analyses have been drawn. 
(See ‘ Bulletin of the Geol. Survey of Victoria,’ No. 24, 1912, and ‘ Proceedings 
of the Royal Society of Victoria,’ vol. xxvi. (N.8.), pt. ii. 1914.) ; 
It was found that by re-calculating the analyses to 100 per cent. with the 
water omitted and the ferric oxide reduced to ferrous, the curves obtained were 
better than those plotted from the original analyses. 
Certain of the analyses did not conform to the curves, and at first these were 
regarded as representing hybrid types, but additional work showed that they 
represented complementary types and resulted from the splitting up of a magma 
instead of the mixing of magmas. 
Some analyses have been made of the alkali rocks from other Victorian areas, 
but Bie a sufficient number to show the relationship of the various types to one 
another. 
