Bull. nat. Hist. Mus. Lond. (Geol.) 52(2): 103-107 
Issued 28 November 1996 
A new deep-water spatangoid echinoid from 
the Cretaceous of British Columbia, Canada 
ANDREW B. SMITH 
Department of Palaeontology, The Natural History Museum, Cromwell Road, London SW7 SBD, U.K. 
ALAN McGUGAN 
1157 Rolmar CR RR 2, Cobble Hill, Vancouver Island, British Columbia, VOR 1L0, Canada. 
Synopsis. A new species of spatangoid echinoid, Plesiaster vancouverensis, is described from continental slope debris flow 
deposits of latest Santonian to early Campanian age on Vancouver Island, British Columbia. 
INTRODUCTION 
| 
The fossil record of echinoids is overwhelmingly dominated by 
species of the continental shelf. Although some of these lived in 
‘elatively deep water settings, such as the faunas of the North-West 
Suropean Upper Chalk facies (Smith & Wright 1989, 1990, 1993), or 
he shelf marginal faunas of Spain (Neraudeau & Floquet 1991) or 
Tunisia (Zhagbib-Turki 1989), records of continental slope and basin 
‘aunas remain extremely rare. Bather (1934) described the holasteroid 
Chelonechinus from the Miocene deep-water Suva Formation of Java, 
and more recently adiverse bathy] echinoid fauna has been discovered 
nthe early Miocene Morozaki Group of Japan (Mizuno 1991) and the 
Middle Miocene Tatsukuroiso Mudstone of NE Honshu, Japan 
‘Kikuchi & Nikaido 1985). Pliocene deposits of California have also 
yielded what appear to be bathy] echinoids (Woodring 1938). Here we 
jescribe a new spatangoid from late Cretaceous outer shelf to upper 
sontinental slope deposits of western Canada. 
| The new species described here comes from a single horizon 
within the Upper Cretaceous Nanaimo Group. The Nanaimo Group 
‘epresents a major sedimentary sequence within the Georgia Basin 
pf south-western British Columbia and was deposited in a fore-arc 
Jasin along the western margin of the Canadian continental margin 
|England 1989). Depositional environments represented within this 
sroup range from alluvial to continental slope facies, with the 
echinoids coming from within a series of debris flows interpreted as 
ipper continental slope facies. 
| The echinoid horizon was discovered in May 1993 by Dr A. 
McGugan and Dr. T. England during reconnaisance of the French 
creek area. The echinoids were found in a stream section adjoining 
dildegard Farm on French Creek, ca. 1 km upstream from Highway 
4 bridge at Coombs, which crosses French Creek approximately 
seven km due south of Qualicum Beach, Vancouver Island, British 
Columbia (Fig. 1). The succession at this locality begins with ca. 6 
n of bedded shales, siltstones and mudstones of the Haslam Forma- 
ion (= lower part of the Trent River Formation of England, 1989; 
sig. 2). These are overlain by a chaotic conglomeratic debris flow 
‘McGugan, 1992). The matrix is a silty mudstone and included 
debbles are a mixture of undated meta-volcanics, argillites, Creta- 
2e0us calcareous concretions (some with plant remains), sandstone 
ind siltstone clasts, and many clasts of bedded shale, some up to 4m 
n length and showing plastic deformation and slump-roll-type 
eading edges. The fauna of these beds include foraminifera, ammo- 
nites and inoceramid and other bivalves. 
The echinoids, all of which belong to the same species, came from 
2 The Natural History Museum, 1996 
a single bedding plane near the top of the bedded shale series. They 
are preserved in life orientation and some at least retain associated 
spines. These echinoids were thus not transported, but lived and died 
within the environment of deposition represented by the shales. 
Since the bedded shales are overlain by debris flows, the environ- 
ment of deposition is taken to be upper continental slope. 
The dating of the echinoid level is based on the benthic 
foraminifera, which are indicative of the Inoceramus (Spheno- 
ceramus) schmidti Zone, latest Santonian to Lower Campanian. The 
associated macrofauna also support a late Santonian — early 
Campanian age. A molluscan fauna (Table 1) is associated with the 
echinoids and in the beds immediately overlying, and has been 
identified by Dr. J.W. Haggart (Geological Survey of Canada, 
Vancouver). This includes /. (S.) schmidti, which is known to range 
from the latest Santonian to early Campanian in British Columbia 
and Northern California (Haggart, 1984). 
Table 1. Fossil molluscs found in association with Plesiaster 
vancouverensis sp. noy. in the Haslam Formation of French Creek, 
Vancouver Island. Identifications by J.W. Haggart (Canadian Geological 
Survey, Vancouver). 
Bivalves: 
Inoceramus (Sphenoceramus) schmidti Michael 
I. ex. gr. subundatus Meek 
Acila (Truncacila) demessa Finlay 
Ammonite: 
Canadoceras yokoyamai (Jimbo) 
SYSTEMATIC DESCRIPTION 
Class ECHINOIDEA Leske, 1778 
Order SPATANGOIDA Claus, 1876 
Family MICRASTERIDAE Lambert, 1920 
Genus PLESIASTER Pomel, 1883 
TYPE SPECIES. Micraster peini Coquand, 1862. 
OTHER SPECIES INCLUDED. P. cotteaui Gauthier. 
OCCURRENCE. Late Coniacian to early Campanian of North Af- 
rica and North America. 
