22 
S. McLoughlin 
Barremian): Figure 2. The Bullsbrook Formation, 
exposed 2 km east of Bullsbrook, is a fully 
continental lateral equivalent of the Leederville 
Formation (Figure 2). 
The Neocomian-?Aptian shallow marine to 
paralic Birdrong Sandstone is chiefly exposed 
along the Murchison River near Kalbarri, on the 
flanks of the Kennedy Ranges, and in the Giralia 
Anticline within the Carnarvon Basin (Hocking et 
al. 1987; McLoughlin et at. 1994). The upper part of 
this unit is typically rich in fragmentary 
permineralized gymnosperm wood showing 
evidence of intensive molluscan borings. Other 
Cretaceous marine units in the Carnarvon Basin 
contain sparse fossil woods, and leaf impressions 
occur within the paralic Nanutarra Formation near 
the Ashburton River (Figure 1). Lignified wood is 
also locally preserved in the Lower Cretaceous 
Nakina Formation, Collie Basin, in the state's 
southwest (Backhouse et al. 1995). 
The Broome Sandstone of the northern Canning 
Basin was deposited within deltaic to shallow 
marine environments whereas the laterally 
equivalent Callawa Formation in the basin's 
southwest is fluvial in origin (Towner and Gibson 
1983). The coeval Cronin Sandstone, outcropping 
in the northwestern part of the contiguous Officer 
Basin (Figures 1,2) was also laid down in fluvial 
environments (Towner and Gibson 1983). These 
plant-bearing units have been regarded as Late 
Jurassic to Early Cretaceous or even fully Jurassic 
on the basis of previous phytostratigraphic 
interpretations (Middleton 1990). However, a 
Neocomian-Barremian age for the plant-bearing 
portions of these units is proposed herein based on 
revised fossil identifications. 
MATERIAL AND METHODS 
The majority of material described and figured 
in this study is held in the collections of the 
Western Australian Museum (specimens prefixed 
WAM) and the Department of Geology and 
Geophysics, University of Western Australia 
(specimens prefixed UWA). Counterparts of some 
of Walkom's (1944) specimens are lodged with the 
Australian Museum in Sydney (specimens prefixed 
AMF). The Commonwealth Palaeontological 
Collection housed by the Australian Geological 
Survey Organisation, Canberra, contains limited 
Canning and Officer Basin material from regional 
geological surveys of the 1950s and 60s and has 
been illustrated by White (1961a). The latter 
material was not re-examined during this study 
but in most cases White's (1961a) illustrations are 
adequate for identification purposes and her 
studied specimens are systematically discussed 
herein. 
All descriptions are based on impression fossils 
preserved in ferruginous shale and medium¬ 
grained quartzose sandstone apart from some 
seeds, megaspores, and axes which are preserved 
as natural clay or sandstone casts. Organic material 
was not preserved on any fossils but in some cases 
latex and silicone casts yielded morphological 
details not clearly evident on negative impressions. 
All specimens were illustrated under strong 
unilateral light directed from the upper left unless 
otherwise stated. 
Fossil localities are as follows: 
Broome Sandstone - Gantheaume Point, Broome 
(material collected by W.H. Butler, A. Dawson, 
I. and T. Foulkes, J. Long, D. and M. Merrilees, 
J. Pas, G. Zeck); Quandong Beach, 10 km north 
of Broome lighthouse (material collected by 
I.M. Doust). 
Nanutarra Formation - Cited as "6.5 km north of 
Globe Hill, Ashburton River" on specimen 
labels (material collected by D.W. McLeod). 
This is probably the plant fossil locality 2.5 km 
north of the junction of Jubricoo Creek and 
Ashburton River, 8 km west of Nanutarra 
indicated by van de Graaf et al. (1980). 
Birdrong Sandstone - Near Toolonga Hill 
(114°16'6"E 27°34'3"S), Murchison House 
Station, 10 km northeast of Kalbarri (material 
collected by S. McLoughlin); 1 km northwest of 
Black Dam (114°10'9"E 23 0 6'3"S), Cardabia 
Station, 35 km east of Coral Bay (material 
collected by D.W. Haig, R. Howe, G. Ellis, S. 
McLoughlin). 
Leederville Formation — Cheriton Creek, about 500 
m east of MacIntyre Gully, 2.5 km north of 
Gingin (material collected by E. de C. Clarke). 
Bullsbrook Formation - 2.5 km northeast of 
Bullsbrook Hotel (material collected by A. 
Page). 
SYSTEMATIC PALAEOBOTANY 
Division Lycophyta 
Class Lycopsida 
Order Isoetales 
Family Isoetaceae 
Genus lsoetites Munster, 1842 
Type species 
lsoetites crociformis Munster, 1842; Jurassic; 
Daiting near Manheim, Germany. 
lsoetites elegans Walkom, 1944 
Figures 3A, C-F 
1944 lsoetites elegans Walkom; p. 202; plate 1, figs 1- 
5. 
