Early Cretaceous macrofloras 
21 
marine invertebrate biostratigraphic indices, the 
ages of many of these rock units are only broadly 
constrained. Furthermore, lack of continuous 
outcrops in many areas hinders the mapping and 
lithological correlation of plant-bearing strata and 
has led to uncertainties over the application of 
lithostratigraphic names. For example, Playford et 
al. (1976) and Skwarko (1990) assigned Walkom's 
(1944) Gingin fossil assemblage to the Yarragadee 
Formation (Middle Jurassic to Tithonian). 
However, Feldtman (1963) reported that the plant¬ 
bearing horizons occurred within the Strathalbyn 
Beds, a term which Playford et al. (1976) regarded 
as synonymous with the Leederville Formation. 
Wilde and Low (1978) also mapped outcrops in the 
vicinity of Walkom's plant beds (Cheriton Creek) 
as part of the Leederville Formation. On the basis 
of lithology and stratigraphic position, the fossils 
are here regarded as belonging to the marine to 
continental Leederville Formation (Hauterivian- 
Fossil leaves 
♦ 
Permineralized wood o 
Figure 2 Stratigraphic correlation of Lower Cretaceous rock units in the Perth, Carnarvon, and Canning Basins, 
Western Australia (after Cockbain 1990; Hocking 1990; Middleton 1990) showing the distribution of plant 
macrofossil assemblages. 
