104 
Area of 
enlargement 
Qualicum 
Beach 
3 Ss 
Parksville 
Fossil echinoid locality 
Fig. 1. Map showing the location of the echinoid bed, with insert showing 
its position on the island of Vancouver. 
Plesiaster vancouverensis sp. nov. Text-figs 3—5 
Types. Holotype, BMNH EE 5078 (Figs 3A, 4A, 4B, 5A); 
paratypes, BMNH EE5076 (Fig. 3C), EES5077, EES079-83 (Figs 
3B, 3D, 3E, 4C-F, 5B). 
OCCURRENCE. Shales towards the top of the Haslam Formation (= 
lower part of the Trent River Formation), /. (S.) schmidti Zone, 
uppermost Santonian to lowermost Campanian, exposed in river 
bank of French Creek behind Hildegard Farm, ca. 1 km upstream 
from the highway 4 bridge over French Creek at Coombs, and 7 km 
due south of Qualicum Beach, south-eastern Vancouver Island, 
British Columbia, Canada. 
DIAGNOSIS. A species of Plesiaster with a well-developed 
peripetalous fasciole around the posterior part of the test, a broad and 
strongly petaloid anterior ambulacrum, and with lateral and poste- 
rior petals broad and open, extending most of the distance to the 
Pachydiscus 
suciaensis 
Campanian 
Bostrychoceras 
elongatum 
Santonian 
England 1989). 
Zone and Subzone 
ree tao Se 
Maastrichtian 
Nostoceras hornbyense 
Metaplacenticeras 
cf. pacificum 
Hoplitoplacenticeras 
vancouverense 
Inoceramus schmidti 
Haslam 
Pachydiscus haradai 
Inoceramus 
naumanni 
Fig. 2. Stratigraphic column for the Upper Cretaceous Nanaimo Group showing the level of the echinoid bed (*) (taken from Muller & Jeletzky 1970, and | 
A.B. SMITH AND A. McGUGAN 
ambitus. The contact between the labral plate and sternal plates is 
strongly offset towards the left-hand side. 
DESCRIPTION. All tests are crushed so accurate dimensions cannot 
be given. The largest and best-preserved specimen is approximately 
63 mm in length and 58 mm in width. Test height and shape in profile 
are unknown, but the test appears to have been relatively low and 
gently domed. The test is oviform in outline with the posterior 
slightly truncated. The widest point on the test lies a little behind the 
anterior petals at approximately mid-length. 
The apical disc is ethmophract with all four genital plates similar 
in size and each bearing a gonopore (Fig. 3B). The posterior genital 
plates are not separated by the madreporite. The apical disc lies 
anterior of centre, 39% of test length from the anterior border. 
All five ambulacra are strongly petaloid adapically. Petals are 
broad and sunken and remain open distally. The anterior petal 
extends 80% of the distance to the ambitus. It shallows and more or 
less disappears towards the ambitus so that the anterior is hardly , 
notched. There are ca. 45 pore-pairs in a column at 63 mm test 
length. The pore-pairs are conjugate, with individual pores widely 
separated (Fig. 3A). The perradial zone is smooth and approxi- 
mately as broad as a single pore-zone (Fig. 5B). The lateral petals : 
extend 90% of the distance to the ambitus and are strongly petaloid, — 
tapering slightly towards the ambitus. They diverge from one an- | | 
other at an angle of 135°. There are ca. 55 pore-pairs in a column at 
———— LS 
63 mm test length. Individual pores are strongly elongate and 
conjugate, with successive pore-pairs separated by single rows of 
miliary tubercles. The posterior petals are similar, but extend only 
75% of the distance to the ambitus. They diverge from one another) | 
at an angle of 50°. Pores below the petals are single. Around the 
peristome there are three to five enlarged phyllode pores. 
Interambulacra are slightly raised adapically but do not form 
sharp keels. They remain biserial to the apex. On the oral surface the: 
primibasal plates in interambulacra 1 and 4 are occluded from the: 
peristome border by proximal ambulacral plates (Fig. 3B). The 
labral plate is elongate and narrow, more than twice as long as broad. 
The sternal plates are clearly differentiated, but unequal in size; that 
towards ambulacrum I being smaller and either just in contact with 
the labral plate (Fig. 3E) or separated from it (Fig. 3D). 
The peristome is small and D-shaped; the labral plate does not 
project over the mouth and there is no distinct lip. The front of the 
peristome lies 19% of the test length from the anterior border. The 
periproct is crushed in all specimens. It lies on the posterior surface: 
and is probably hidden in both apical and oral views. 
Formation 
Cedar District 
Extension 
Protection 
Comox 
