34 
E. DE C. Clarke and C. Teichert. 
large (iiiartz grains. In view o£ the fact lliat the base of the Butte 
Sandstone is in general nut well exposed, being buried under loose material 
slid down from above, it is not known whether this mottled sandstone 
zone has a very wide distribution. 
In the uppermost ID feet or so tlie loose quartz sand changes into 
glauconitic and ferruginous loosely cemented sandstone. 
South-west of Tooloiiga Point, at Thirindine, and in the gully north 
of \althoo windmill there is a somewhat gradual transition to the over- 
lying Ihiriudino Shales j the (pmrtz sand first becomes glauconitic, and 
the size of the quartz grains gradually diminishes until the deposit 
becomes a glauconitic clay; tlien the glauconite disapj)ears and the transi- 
tion to the overlying shales is complete. Farther south-west, at Second 
Gully Point, the I:oundary Avith the overlying shales is better marked, 
the top of the Butte Sandstone l)ping a broAva loose sand with ferruginous 
concretions. 
F'ossils. fossil Avond Avas found in a few places in the u[)permost two 
feet of the Butte Sandstone, notably to the south-west of Toolonga Point 
and at Thirindine Point. Some of the wood fragments are riddled Avith 
cylindi i<'*)l huiiOAA's, ju'ohahly made l)y a 7 crcdo-like mollusc. Their presence 
suggests that the Avood must have drift(‘d for some time hefoi’e it became 
■embeddeil iu the saud. Very poor silicified l)e|{‘mnite fragments were found 
in the dills west of the emergency aerocli*ome four miles north of Bettie. 
Definitely recognizable tracks and burroAvs \vcrc only seen in one place 
in the hard (juartz sandstone layers near the top of the Butte Sandstone 
in tlie Pillnrawa st'ction. Vertical and oblique burrows, up to one inch 
Avide, jienelrate this sandstone bed to a depth of one to 10 inches. On 
the kedding plane the entrance to these hurroAA-s is surrounded by circular 
walls Avhidi are Iavo to three mm. high. In addition, the bedding plane 
is covered l)y a network of shallow, sometimes winding, but more often 
stiaight i iiri'OAA s, obviously the trails of some crawling iiiA’ertebrates. 
Most of these trails seem to bypass the openings of the vertical buiTows, 
but some issue trom them, so that it is reasonable to assume that both 
ImrroAvs and trails have been made by the same kind of animal, most 
probably a worm. ' ’ 
In the running sand of the Toolonga section long tube-like structures 
were observed AAdiic.h are about five mm. wide and up to 10 and 15 cm. 
long and are either vertical or inclined up to an angle of G0°. They 
aie foimed of sand grains Avhich are very loosely cemented and are 
occasionally brought out by Aveatheriug, the surrounding matrix being ' 
quite incoherent. Tt is believed that these structures are also due to the 
activities of some burrowing animals. 
TJiiclaiess.~The thickness of the Butte Sandstone varies rather consider- 
ably. In the PillavaAva section it is about 100 feet, farther east the 
sandstone is not sufiieiently well exposed for measurements of thickness 
to be taken. Farther west in the Toolonga Hills the thickness increases 
from M to lOo feet in a Avesterly direction. From there it increases 
probably rather regularly until it reaches 170 feet at the butte in Second 
Gully, the maximum thickness measured, and 152 feet at Second Gully 
Point. At Meanarra there must be about 50 feet of Butte Sandstone. 
