214 WALTER HOWCHIN 
of glacial origin” (XXVIII, p. 28), and figured four glaciated 
bowlders (plate IV) from these localities. The deposit was proved 
to exist for a distance ‘‘considerably over sixty miles.” 
In Bulletin No. to, Geological Survey of Western Australia, 
plate VI, Mr. Maitland maps the approximate line of outcrop of 
the ‘glacial conglomerate’? between the Wooramel and Minilya 
rivers. 
Mr. Maitland, in a presidential address (XXIX, p. 146), gave 
further particulars and says, 
At the most southerly locality at which the bowlder bed has been detected 
in Wooramel Valley, the bowlders are of very large size, and are composed of 
rocks identical in character with those forming the older underlying rocks to 
the east, e.g., granite and other crystalline and metamorphic rocks. Some 
distance northward, on the Wyndham River, is a bowlder bed in the limestone 
series. The bed, which at this spot attains no greater thickness than 3 ft., 
is crowded with bowlders and pebbles of granite and crystalline rocks embedded 
in a calcareous fossiliferous matrix . . . . the pebbles and bowlders have a 
large proportion of smooth and polished faces. 
The same beds are further described by Maitland in their 
northern extension to the Minilya River. 
Assistant Government Geologist, W. D. Campbell, in a detailed 
examination of the Irwin River Coalfield (situated 300 miles to the 
south of the Gascoyne, where Maitland’s observations were made), 
paid special attention to the glacial beds of the section and has 
supplied interesting photographs of the features (XXX). He 
refers the glacial beds to the middle of the Permo-Carboniferous 
series, or about the horizon of the Greta Coal Measures of New 
South Wales. The erratics comprise granite, gneiss, amygdaloids, 
quartzites, sandstones, chalcedonized sandstones, and limestones, 
mostly rounded and many with smoothed surfaces and some with 
well-defined grooves and cross-scratchings, such as only glacial 
action can produce. These form in places extensive bowlder beds 
or outcrops which occur at distances of from 5 to ro miles from the 
main granite margin. These erratic blocks are mostly identifiable 
with rocks forming the tableland eastward of the main granite 
range. The largest outcrop of the bowlder beds is on the west 
side of the Irwin River, at Nangatty, and is about 4 miles long 
and 2 miles wide (XXX, p. 39, pls. XIV-XVIII). 
