Tertiary Deposits Near Norseman, Western Australia. 
89 
Princess Koyal deposits. AVe also visited an area near the northern end 
of Lake Dundas, where (Campbell had reported the occurrence of unfossili- 
ferous dolomites. 
5. acknowledgments. 
The expenses of the excursion were defi'ayed by the Commonwealth 
Research Grant to the I'uiversity of AVestern Australia. Transport in 
the Norseman district was generously provided by Central Norseman Gold 
Alines. AA"e wish to express our gratitude to Air. AA", Lindesay Clark, 
director of the AA’^estern Alining Corporation, to Air. 11. AY. TL Talbot, 
geologist to the Corporation, and to Air. AA^. Dutton, supeihntendent of the 
Central Norseman Gold Alines for their courtesy and help, without which 
these observations could not have been made. AVe are also indebted to 
Dr. R. T. Prider for help in revising the text. 
II. SITUATION OF OUTCROP AREAS OF THE TERTIARA^ 
SEDIAIENTS. 
So far as known at present the T(*rtiary sediments occur in patches, 
isolated by erosion, along the east side of Lake Cowan and near the north 
end of Lake Dundas about five miles north-east of Norseman. The occur- 
rences which we examined may be grouped into the following live ^'outcrop 
areas” : — 
(1) CampbelUs '^opalized sea beach,” three miles north of Norse- 
man. 
(2) The spongolite deposits which underlie part of the old Princess 
Royal Townsite and extend west of it. To the north, between 
Princess Royal and Lake Cowan and on the shores of the 
lake itself are several disconnected patches of unfossiliferous 
dolomite which might be included in this outci*op area. 
(3) A number of limestone aud dolomite outcrops, mostly fossili- 
ferous, along the north side of the Peninsula, about 15 miles 
jiorth of Norseman. 
(4) Unfossiliferous dolomite outcrops on the north shore of Lake 
Dundas, live miles north-east of Norseman. 
(5) A spongolite occurrence at the north end of Lake CoAvan. This 
was visited by one of us (E. de C.C.) many years ago. 
It is to be expected that a close survey of the shores of Lake Cowan 
and Lake Dundas Avill reveal the presence of additional outcrops. 
III. ROCK TA^PES. 
There are three main roek types in these Tertiary deposits: — spongo- 
lite, unfossiliferous dolomite, and fu.ssiliferous limestone and dolomite. 
1. The spongolite is jjorous, Avhite to orange-red in colour, and very 
light in Aveight. It is composed of the spicules of siliceous sponges of 
which many species Avere identified liy Hinde (I-9T0)» Associated with 
the typical spongolite are beds of blue clay and white shale only a feAV 
feet thick. The blue clay is a light bluish-grey rock Avith occasional Avhito 
