194 
K.J. McNamara 
Figure 1 Map showing the locations of fossil Peronella 
in the Carnarvon, Perth and Eucla Basins, 
Western Australia. 
southeastern arm of Shark Bay, immediately north 
of Hamelin Pool and the Faure Sill (Figure 1). The 
bed containing the echinoids is a fossiliferous 
limestone, less than one metre in thickness, that 
outcrops at Wooramel Cliff, Gladstone Bluff, 
Gladstone Jetty and in gullies along the Toolonga 
Scarp (Logan et al. 1970). The specimens used in 
this study were collected from approximately 2 km 
south of Gladstone Jetty to about 100 m north of 
the Jetty, from outcrops of limestone that occur in 
the intertidal zone, 200-300 m seaward of high 
water mark. 
This limestone was termed the "Gladstone unit" 
by Davies (1970), and was regarded by Logan et al. 
(1970) as being laterally equivalent to the basal 
beds of the Carbla Oolite. Playford et al. (1975) 
called this unit the Gladstone Member of the 
Carbla Oolite. This classification is followed herein. 
The Carbla Oolite was provisionally considered by 
Kendrick et al. (1991) as being correlated with 
Oxygen Isotope Stage 7 (220,000 - 235,000 BP) of 
the Middle Pleistocene. 
In addition to the presence of the species of 
Peronella, this unit has yielded the spatangoid 
echinoid Breynia desorii (Gray), a species which is 
still living in Shark Bay today (McNamara 1982). In 
addition, there is a molluscan fauna that includes 
Pecten modestus Reeve, Dendostrea folium (Linnaeus), 
Fragurn (Lunulicardia) sp., Circe sp., Tagelus sp., 
Clementia papyracea (Gray), Dosinia (Pectunculus) cf. 
sculpta (Hanley), and Strombus (Doxander) campbelli 
Griffith and Pidgeon (specimens WAM 87.528 to 
87.535, identified by G.W. Kendrick). The 
foraminifer Marginopora vertebralis Blainville is also 
a common element, indicating, as Logan ef al. 
(1970) suggested, that this "Peronella assemblage" 
occupied open sandy patches in seagrass 
meadows. 
Overlying the Gladstone Member in the eastern 
part of Shark Bay is a unit of shelly calcarenite, 
containing well-preserved aragonitic shell, which 
is probably equivalent to the Dampier Formation. 
A small species of Peronella, attributable to the 
living species P. orbicularis, occurs in this unit. The 
same species has been recovered from the Dampier 
Formation on the Peron Peninsula. Rarely more 
than 1 m in thickness, the Dampier Formation is a 
bivalve-rich limestone and lithoclast grainstone. 
While this formation was considered by Logan et 
al. (1970) to be of Middle Pleistocene age. Uranium- 
series dates from the coral Coniastrea (Kendrick et 
al. 1991) indicate a Late Pleistocene, Last 
Interglacial, age for this formation. 
The oldest species of Peronella to occur in 
Western Australia is found in the Eucla Basin in 
the Roe Calcarenite. While Foster and Philip (1980) 
followed Ludbrook (1978) in ascribing a Pleistocene 
age to this richly fossiliferous unit, Kendrick et al. 
(1991) favoured a Late Pliocene age, on the basis of 
the nature of the molluscan fauna. Unfortunately, 
the echinoid fauna, as described by Foster and 
Philip (1980), provides no corroborating evidence 
one way or the other. In addition to Peronella, 
Foster and Philip (1980) recorded Microcyphus 
annulatus Mortensen, Amblyneustes formosus 
Valenciennes and Amblyneustes sp. nov. 
Specimens referred to in this study are housed in 
the invertebrate palaeontology collections of the 
Western Australian Museum (WAM) and the 
Natural History Museum, London (BMNH). 
Measurements were made with an electronic 
calliper to an accuracy of 0.01 mm. A number of 
parameters are expressed as percentages of test 
length (%TL). 
SYSTEMATIC PALAEONTOLOGY 
Order Clypeasteroida A. Agassiz, 1872 
Family Laganidae A. Agassiz, 1872 
Genus Peronella Gray, 1855 
Type species 
Laganum peronii L. Agassiz, 1841: 123; by original 
designation 
