Robert Etheridge, of the Australian Museum, Sydney, but on 
account of their poor state of preservation, he has been unable to 
state their age more definitely than (taking the substance of his 
statements for various localities in impul)lished letters to the 
Geological Survey of Western xA.ustralia) as “either recent or 
young Tertiary.’* ** 
On the other hand the most definite evidence in regard to the 
age of the Plantagenct Series is afforded by the fossil .-ituria 
australis (McCoy), a cephalopod. having in Victoria, according to 
McCoytt, and Chapnian$t, a range from Oligoccne to Lower 
Pliocene. One specimen of this was determined some years ago 
l)y R. Etheridge, Junior, in material from Cape Riche, and a 
second (piite recetitly by T.. (dlanert in undoubted S])icular silt of 
the Plantagcnet Series from the Bremer River**, 10(i miles north- 
east of Al1)any, In view of the occurrence of this fossil, and 
of the known extensive sul>mergence of Southern Australia during 
Miocene times, the authors ‘believe that the Plantagenct series will 
ultimatelv be determined as of Miocene age. 
From a ])hysiographic and geological i}oint of view, it is very 
necessary that a detailed examination should be made of the fossils 
contained in these widesjmead dci)osits. The same remarks apply 
to other fossiliferous rocks of comparatively late age in the 
southern ])ortion of this State ( e.g., those at Lake Cowan) which 
may ultimately be correlated with the Plantagenct Series. 
LATCH rOKMAl'KJXS. 
The rock known as the “Coastal Limestone” occurs ond^ortion? 
of the crest and sloi)es facing the ocean of the high ridge between 
IVincess Royal Tlarbour and King George's Sound on the north, 
and the Southern Ocean on the south, to which reference has 
already been made. Charles Darwin, during the famous voyage 
of the “Beagle” lande<l near P>ald Head and made various ob.scr- 
vations there. As the ridge referred to hears no distinctive name, 
we propose lo term it the "Darwin Ridge,” in honour of the great 
naturalist who first studied its structure. The coastal limestone 
mav be ol)servcd covering and j)lastering over the granite, which 
from its numerous outcro])S at all heights from sea-level to crest 
may be rcgarderl as the back bone of the ridge. i\Tr. Maitland has 
described this limestone and considers it to be of aeolian origin, 
a conclusion reached independently by the authors, who have 
observed that it is comi)osed mainly of foraminifera and fragments 
of calcareous algae, which have been blo^\T^ into their i)resent 
*See Bulletin 26 of the Geological Survey of Western Australia, p. 
60. 
I't kalaeotology of Victoria, Decade III., PI. xxiv., pp. 21, 22. 
ft “Australasian Lossils,” 1914, p. 210. 
** Bremer River runs into Bremer Bay. 
