258 
Professor Tate made a still more emphatic statement of 
his views on this subject in his inaugural address before the 
Australasian Association for the Advancement of Science, 
held in Adelaide in 1893. Ia dealing with the "Fundamen- 
tal or Archean Rocks" of Australia, he said:— "The gen- 
eralisation which has sought to sweep all the crystalline rocks 
of Australia into the great Silurian net has been broken 
down by the discovery of unconformably super-imposed Cam- 
brian strata, and, though it by no means follows that the 
whole of the crystalline rock masses are of Archæan age, yet 
there are good reasons for the belief that those rocks which 
exhibit the phenomenon of regional metamorphism belong 
to one epoch. . . . The grandest exemplification of the 
Archæans is in the Mount Lofty Range of South Australia. 
These rocks occupy there a vast monocline, with a dip to the 
south-east of not less than ten miles in thickness. One note- 
worthy lithological feature is the more highly developed meta- 
morphism of the upper strata, mica schists, gneiss, and 
granite succeeding, in an ascending series, clay slates, quart- 
zites, and limestones. This exceptional phenomenon was 
recorded by Jukes in 1850: “The prevailing south-easterly 
dip would put the clay slates under the gneiss, mica, and 
chlorite slates’; and independently observed by Selwyn,* in 
1860 [(?) 1859]. The non-acceptance of this view by the 
Government Geologist of South Australia has compelled him 
to reverse the order of succession, and he classes the lower 
series as ‘Silurian (and Devonian) metamorphic in part,’ and 
relegates the upper to ‘Paleozoic or Azoic, highly metamor- 
рше 
In a new edition of the geological map of South Aus- 
tralia by Mr. H. Y. L. Brown, Government Geologist, pub- 
lished іп 1899, the Mount Lofty Ranges are defined as “Салп- 
brian and (?) Lower Silurian.” Later discoveries have 
strengthened the positions of Selwyn, Brown, and others, 
who have held that the Mount Lofty Ranges, in the main, 
belong to a post-Archæan age, and have an inferior order of 
succession from west to east, rather than those views so 
strongly held by Professor Tate. 
An important factor in the chain of evidence was obtained 
when, in 1897, Professor David and the writer discovered 
Archeocyathine remains in the limestones of Normanville, 
which were subsequently traced along the line of strike for 
a distance of twenty-five miles, to a point three miles to the 
* I cannot draw the same inferenoe from Selwyn’s report on 
+ Aus. Ass. Ad. Se., vol. v., p. 45, et. seq. 
