Life Sciences Contributions
Royal Ontario Museum 1 a0
Llandoverian Graptolites of the
Northern Canadian Cordillera:
Petalograptus, Cephalograptus,
Rhaphidograptus , Dimorphograptus,
Retiolitidae, and Monograptidae
Alfred C. Lenz
ey
ROM
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LIFE SCIENCES CONTRIBUTIONS
ROYAL ONTARIO MUSEUM
NUMBER 130
ALFRED C. LENZ Llandoverian Graptolites of the
Northern Canadian Cordillera:
Petalograptus, Cephalograptus,
Rhaphidograptus, Dimorphograptus,
Retiolitidae, and Monograptidae
fs
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ROYAL ONTARIO MUSEUM
PUBLICATIONS IN LIFE SCIENCES
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particular field involved.
LIFE SCIENCES EDITORIAL BOARD
Senior Editor: C. MCGOWAN
Editor: P.H. von BITTER
Editor: R. WINTERBOTTOM
ALFRED C. LENZ is Professor of Geology, Department of Geology, University of Western Ontario, London,
Ontario N6A 5B7.
Canadian Cataloguing in Publication Data
Benz, Au.
Llandoverian graptolites of the northern Canadian
Cordillera
(Life sciences contributions, ISSN 0384-8159; no. 129)
Bibliography: p.
ISBN 0-88854-279-8
1. Graptolites. 2. Paleontology—Silurian.
3. Paleontology—Northwest Territories. 4. Paleon-
tology—Yukon Territory. I. Royal Ontario Museum.
He Witle.« ME Series:
QE840.5.L46 566 C81-0949 15-6
Publication date: 14 January, 1982
ISBN 0-88854-279-8
ISSN 0384-8159
© 1982, The Royal Ontario Museum
100 Queen’s Park, Toronto, Canada MSS 2C6
PRINTED AND BOUND IN CANADA AT THE ALGER PRESS
Contents
Abstract Hl
Introduction /1
Materials and Methods [2
Stratigraphy Is
Biostratigraphy /5
Systematic Palaeontology /9
Genus Petalograptus Suess, 1851 J 10
Petalograptus altissimus Elles and Wood, 1908 /10
Petalograptus elongatus (Boucek and Pribyl, 1941) jal
Petalograptus folium (Hisinger, 1837) jal
Petalograptus cf. hispanicus Haberfelner, 1931 /14
Petalograptus intermedius (Boucek and Pribyl, 1941 /16
Petalograptus ovatoelongatus (Kurck, 1882) fAT
Petalograptus cf. palmeus palmeus (Barrande, 1850) /19
Petalograptus cf. palmeus clavatus (Bouéek and Pribyl, 1941) /20
Petalograptus cf. palmeus praecedens (Bouéek and Pribyl, 1941) /21
Genus Cephalograptus Hopkinson, 1869 12)
Cephalograptus cometa cometa (Geinitz, 1852) (21
Cephalograptus cometa extrema Boucéek and Pribyl, 1941 /24
Cephalograptus tubulariformis (Nicholson, 1867) /24
Genus Dimorphograptus Lapworth, 1876 }25
Dimorphograptus confertus swanstoni Lapworth, 1876 [25
Dimorphograptus cf. physophora (Nicholson, 1868) /28
Dimorphograptus physophora alaskensis Churkin and Carter, 1970 /29
Genus Rhaphidograptus Bulman, 1936 (30
Rhaphidograptus sp. /30
Rhaphidograptus cf. toernquisti (Elles and Wood, 1906) [a2
Genus Retiolites Barrande, 1850 12
Retiolites decurtatus Boucek and Munch, 1943 [32
Retiolites geinitzianus angustidens Elles and Wood, 1908 [33
Genus Stomatograptus Tullberg, 1883 / 36
Stomatograptus grandis grandis (Suess, 1851) / 36
Stomatograptus grandis imperfectus (Bouéek and Minch, 1943) eg)
Stomatograptus sp. / 40
Genus Pseudoplegmatograptus Pribyl, 1948 / 40
Pseudoplegmatograptus giganteus (Bouéek and Minch, 1943) /41
Pseudoplegmatograptus obesus obesus (Lapworth, 1877) /41
Pseudoplegmatograptus obesus reticulatus (Bouéek and Miinch, 1943) /42
Pseudoplegmatograptus obscurus (Boucek and Minch, 1943) / 44
Genus Lagarograptus Obut and Sobolevskaya, 1968 /45
Lagarograptus cf. acinaces (Tornquist, 1899) /45
Lagarograptus inexpeditus Obut and Sobolevskaya, 1968 /47
Genus Atavograptus Rickards, 1974 /48
Atavograptus cf. gracilis Hutt, 1975 /48
Atavograptus strachani (Hutt and Rickards, 1970) / 49
Genus Coronograptus Obut and Sobolevskaya, 1968 /50
Coronograptus cf. cyphus (Lapworth, 1876) /50
Coronograptus gregarius gregarius (Lapworth, 1876) lis
Coronograptus gregarius arcuatus Obut and Sobolevskaya, 1968
Coronograptus hipposideros (Toghill, 1968) [33
Genus Pribylograptus Obut and Sobolevskaya, 1966 [35
Pribylograptus angustus (Rickards, 1970) /56
Pribylograptus cf. argutus (Lapworth, 1876) /56
Pribylograptus sp. [a7
Genus Pristiograptus Jaeckel, 1889 /58
Pristiograptus nudus (Lapworth, 1880) /58
Pristiograptus regularis (Tornquist, 1899) /60
Pristiograptus cf. variabilis (Perner, 1897) /61
Genus Monoclimacis Frech, 1897 /63
Monoclimacis linnarssoni (Tullberg, 1883) i633
Genus Monograptus Geinitz, 1852 emended /64
Monograptus cf. argenteus (Nicholson, 1869) /64
Monograptus circularis Elles and Wood, 1913 /65
Monograptus clingani (Carruthers, 1867) /65
Monograptus communis Lapworth, 1876 /67
Monograptus convolutus (Hisinger, 1837) /69
Monograptus aff. cygneus Tornquist, 1892 /70
Monograptus crispus Lapworth, 1876 /70
Monograptus curvus Manck, 1923 [73
Monograptus decipiens decipiens Tornquist, 1899 /74
Monograptus decipiens valens Pribyl and Munch, 1942 we
Monograptus cf. denticulatus Tornquist, 1899 /76
Monograptus cf. elongatus Tornquist, 1899 {79
Monograptus exiguus primulus Boucek and Pribyl, 1942 /79
Monograptus falx (Suess, 1851) / 80
Monograptus flagellaris Tornquist, 1892 /81
Monograptus involutus Lapworth, 1876 /82
Monograptus cf. knockensis Elles and Wood, 1913 /85
Monograptus lobiferus harpago Tornquist, 1899 / 86
Monograptus marri Perner, 1897 /87
Monograptus millepeda (M’Coy, 1850) /88
Monograptus minimus Bouéek and Pribyl, 1951 pon
Monograptus cf. mirus Perner, 1897 pon
Monograptus cf. pandus Lapworth, 1877 [92
Monograptus parapriodon Bouéek, 1931 (93
Monograptus planus planus (Barrande, 1850) /94
Monograptus planus obtusus Schauer, 1971 /97
Monograptus priodon (Bronn, 1835) /97
Monograptus proteus (Barrande, 1850) /98
Monograptus pseudobecki Boucek and Pribyl, 1942 /99
Monograptus revolutus Kurck, 1882 /100
Monograptus cf. revolutus Kurck, 1882 /103
Pas,
Monograptus rickardsi minor Hutt, 1975 / 104
Monograptus runcinatus richardsonensis subsp. nov. / 104
Monograptus cf. sartorius Tornquist, 1881 /105
Monograptus sedgwicki (Portlock, 1843) / 106
Monograptus sidjachenkoi (Obut and Sobolevskaya, 1965) / 109
Monograptus speciosus Tullberg, 1883 /110
Monograptus spiralis (Geinitz, 1852) JOU
Monograptus spiralis cf. contortus Perner, 1897 pA
Monograptus cf. tenuissmus (Obut and Sobolevskaya, 1968) UES
Monograptus triangulatus fimbriatus (Nicholson, 1868) /116
Monograptus cf. triangulatus separatus Sudbury, 1958 /116
Monograptus tullbergi spiraloides (Pribyl, 1944) /117
Monograptus turriculatus (Barrande, 1850) jAIS
Monograptus cf. undulatus Elles and Wood, 1913 pa2
Genus Rastrites Barrande, 1850 PA2ZZ
Rastrites approximatus Perner, 1897 P1222
Rastrites approximatus geinitzi Tornquist, 1907 (728
Rastrites distans Lapworth, 1876 /124
Rastrites cf. distans Lapworth, 1876 /124
Rastrites cf. hybridus Lapworth, 1876 jae
Rastrites linnaei Barrande, 1850 /128
Rastrites longispinus Perner, 1897 /128
Rastrites maximus Carruthers, 1867 /129
Rastrites orbitus Churkin and Carter, 1970 /130
Rastrites cf. perfectus Pribyl, 1942 (132
Rastrites phleoides Tornquist, 1887 j33
Rastrites rostratus sp. nov. (535
Genus Diversograptus Manck, 1923 / 134
?Diversograptus ramosus Manck, 1923 P35
Genus Barrandeograptus Boucek, 1933 1/135
Barrandeograptus aff. pulchellus (Tullberg, 1883) / 136
Acknowledgements Hs)
Literature Cited /138
Appendix /145
Digitized by the Internet Archive
in 2011 with funding from
University of Toronto
http://www.archive.org/details/llandoveriangrap0Olenz
Llandoverian Graptolites of the
Northern Canadian Cordillera:
Petalograptus, Cephalograptus,
Rhaphidograptus, Dimorphograptus,
Retiolitidae, and Monograptidae
Abstract
Llandoverian graptolite faunas from 13 major sections in a region
extending from the southern Northwest Territories to northern Yukon
are divisible into 13 zones, of which the persculptus and magnus zones
are only tentatively recognized. The biostratigraphic units, from oldest
to youngest, are the persculptus Zone?, acuminatus Zone, atavus
Zone, acinaces Zone, gregarius Zone, triangulatus Zone, magnus
Zone?, argenteus Zone, convolutus Zone, sedgwicki Zone, tur-
riculatus Zone, spiralis Zone, and sakmaricus-laqueus Zone.
This study describes 101 species of graptolites. The number of
species described for each genus is as follows: nine species of
Petalograptus, three of Cephalograptus, two of Rhaphidograptus ,
three of Dimorphograptus , two of Retiolites , three of Stomatograptus ,
four of Pseudoplegmatograptus, two of Lagarograptus, two of
Atavograptus, four of Coronograptus, three of Pribylograptus, three
of Pristiograptus, one of Monoclimacis, 46 of Monograptus, 12 of
Rastrites, and one each of ?Diversograptus and Barrandeograptus .
One new species, Rastrites rostratus, and one new subspecies,
Monograptus runcinatus richardsonensis, are described.
Introduction
Graptolite-bearing strata encompassed, at least in part, within the Road River
Formation, are widespread throughout the northern Canadian Cordillera. Geogra-
phically they extend from the northern Rocky Mountains of northern British
Columbia in the south, through the central and western Mackenzie Mountains and the
Selwyn Mountains, to the Barn Mountains in northern Yukon in the north. Depending
on the locality, the age of the graptolite facies ranges from Late Cambrian through to
late Early Devonian. That age range, in conjunction with the fact that some sections
are essentially unbroken homoclinal sequences, make these sucessions ideal for
biostratigraphic zonation.
A number of previous studies of the northern Cordillera (Jackson and Lenz, 1962;
O’Bertos and Jackson, 1963; Lenz and Jackson, 1964; Jackson et al., 1965; Lenz and
|
Pedder, 1972; Lenz, 1978, 1979) have gradually built up an increasingly refined
zonation of the graptolite faunas. Taxonomic studies of western North American
Llandoverian graptolites are few, and are by Churkin and Carter (1970) in
southeastern Alaska, Berry and Murphy (1975) in Nevada, Carter and Churkin (1977)
in Idaho, and Lenz (1978) in northern and Arctic Canada. The most detailed and
refined biostratigraphic treatment of the Llandoverian faunas of the northern
Cordillera is in Lenz (1979). The purpose of this paper is the description and
illustration of Llandoverian graptolites of the northern Canadian Cordillera.
The common diplograptids Climacograptus, Diplograptus, Glyptograptus, Or-
thograptus, and Pseudoclimacograptus are identified only cursorily and listed, but
are not described in this study. Cyrtograptus is also excluded because it was the
subject of an earlier study (Lenz, 1978).
Materials and Methods
The graptolites which form the basis of this study were collected from well-exposed
sections of the Richardson and Ogilvie Mountains, northern Yukon, and from the
central and southern Mackenzie Mountains, Northwest Territories. The sections were
measured in feet (pre-1977) or metres (post-1977) above a datum, and each graptolite
collection was assigned a collection number corresponding to the actual metres (or
feet) above the datum; subsequently, all non-metric measurements were converted to
metres. The datum differs for each section, and requires explanation.
The Peel River section was measured, almost in its entirety in 1971, beginning in
the earliest Ordovician?, Tremadocian strata (see Lenz and Pedder, 1972). The same
section was recollected in much greater detail in 1977 and 1978, beginning just below
the Ordovician-Silurian boundary, but for consistency, the 1971 measurement
numbers, and therefore collection numbers, were used. Subsequently, collection
numbers were converted to metres.
Blackstone River section was measured beginning about 50 m_ below the
Ordovician-Silurian boundary and continuing to the top of exposed Silurian strata,
corresponding to the spiralis Zone.
Tetlit Creek and Rock River sections were sampled from below the Ordovician-
Silurian boundary to above the top of the Llandovery strata.
Mount Sekwi section (locality 9), which is structurally overturned, was collected
from stratigraphically youngest to oldest, beginning in Upper Silurian beds.
Delorme Range (locality 10) and Whittaker Range (locality 11) were collected by
J. Etherington in 1965, beginning at the base of graptolite-bearing strata.
Finally, Clearwater Creek (locality 12), which was collected by J. Etherington in
1966, begins at the top of a prominent quartzite unit which appears to mark the
highest Ordovician beds in the area.
Under the heading Occurrence in the Systematic Palaeontology section, the
occurrence of each species is listed by its zonal occurrence(s), localities where
collected, and the stratigraphic level (in metres) at which collection was made. The
stratigraphic intervals listed are precisely the same as those listed in the complete
faunal list in the appendix.
The large collection of graptolites from northern Canada were identified using
standard techniques, on the basis of a very extensive literature survey of most major
and minor taxonomic works, as well as a comparison with material in the type
collections of the Sedgwick Museum of Geology, Cambridge University; the British
Museum (Natural History); and the Department of Historical Geology and
Palaeontology, Copenhagen University. Measurements of parameters, utilized in the
identification and differentiation of species, was by means of a vernier eyepiece in a
binocular microscope; this permitted an accuracy of measurement of about 0.5 mm.
Synonymies given in the systematic section of this paper are generally selective,
and do not necessarily list all publications perused in the identifications of the species;
instead, they list the more important taxonomic literature used in this study.
The appendix lists all species identified in the course of this study, including those
not described or illustrated.
Under the heading Material in the taxonomic section, a number of terms are used in
describing the condition of preservation of specimens of each species. These terms
and their explanations are as follows: poor (preservation)—low contrast with rock,
details of thecae not clear; fair—outline of rhabdosome clear, thecal characteristics
overall generally discernible; moderate—good contrast with rock, outline of
rhabdosome clear, gross thecal characteristics readily discernible; moderately
well—good contrast with rock, thecal characteristics fairly clear and unambiguous;
well—strong contrast with rock, thecae flattened but otherwise undeformed, most
thecal subtleties recognizable; very well—very strong contrast with rock, thecal
outlines crisp, thecal subtleties including introversion and retroversion clearly visible.
Stratigraphy
Graptolite-bearing strata of the Richardson Mountains and the adjacent Ogilvie
Mountains, Yukon, were assigned to the Road River Formation by Jackson and Lenz
(1962). Subsequently the formation has been recognized in east-central Alaska,
northern Yukon, central and southern Mackenzie Mountains, western Northwest
Territories, and northeastern British Columbia (Fig. 1).
Lithically, the Road River Formation varies markedly from locality to locality.
Typically it consists of dark shale, dark bedded chert, and dark limestone with
occasional mass-flow lenses, conglomerates, and turbidites. The formation encom-
passes strata of greatest age range in the Richardson Mountains. Here, strata at the
base are Late Cambrian in age, while those at the top are late Early Devonian.
Graptolites are abundant throughout the entire sequence of Llandovery strata,
although they are concentrated primarily in the shales, and are rare in the cherts and
limestones. Benthic, non-graptolite faunas are rare, and when present, generally
show good evidence of being allochthonous.
Llandovery strata of the Road River Formation comprise various combinations of
shales, cherts, and calcareous shales, and occasional mass-flow deposits (see Lenz,
1972). Their contacts with the underlying Ashgill (Ordovician) and overlying
Wenlock (Silurian) strata appear to be gradational, although there is no clear-cut
evidence of the presence of the earliest Silurian persculptus Zone (see Lenz, 1979).
Llandovery strata range from as little as 90 m to at least 250 m in thickness
throughout the region (Lenz, 1979).
feiss Rs ae
1
2
TERRITORY
A
2
ry wwii i]
AWhitehorse a \
;
oF ort Nelson
BRITISH eae
100
200
Fig. 1. Map of Yukon and adjacent western Northwest Territories showing 13 graptolite localities which
form the basis of this study. Localities are as follows:
iN
Rock River, north tributary, 66°55’N, 136°14’W;
2. Rock River, south tributary, 66°48’N, 136°16’W;
3. Tetlit Creek, tributary of Road River and type section of the Road River Formation, 66°44’N,
135°47'W;
4. Road River, 66°34'N, 135°43’'W;
5. Unnamed creek on west side of Richardson Mountains, 66°30’N, 136°15'W;
6. Peel River, upper canyon, 65°53'N, 135°43'W;
7. Blackstone River, 65°24'’N, 137°16'’W;
8. Pat Lake, 65°07’N, 136°41'W;
9. Mount Sekwi, 63°29’'N, 128°38'’W;
10. Delorme Range, 62°45’N, 125°15’W;
Whe
Whittaker Range, 62°28.5’N, 124°48'W;
12. Clearwater Creek, 61°35'N, 125°35'W;
13. Beaver River, 60°30’N, 125°58'W.
4
Biostratigraphy
The graptolite-based biostratigraphic zonation of the Llandovery sequences of the
northern Cordillera, with an accompanying range chart of all the known taxa to 1977,
was given by Lenz (1979). That zonal scheme was in turn based in part on
modifications of zonal schemes of Churkin and Carter (1970), Rickards (1970),
Koren’ (1973), Hutt (1975), Bjerreskov (1975), and Rickards (1976a) (see Table 1
for correlation of zonal schemes).
Thirteen biostratigraphic zones, of which the lowest is tentative, are recognized in
the Llandoverian graptolite faunas of the northern Cordillera. Because graptolite
diversity is high throughout the Llandovery, most of the recognized zones are
assemblage zones, that have had the first appearance of new taxa added. For
example, the turriculatus Zone is recognized by an association of Monograptus
turriculatus, M. exiguus exiguus and/or M. exiguus primulus, M. runcinatus, M.
planus obtusus, and Pseudoplegmatograptus obesus reticulatus; but its base is
recognized by the first appearance of the first two taxa. On the other hand the spiralis
Zone is recognized by the acme of M. spiralis (even though it begins in the
underlying zone) in association with the first appearance of M. priodon, M. curvus,
Retiolites geinitzianus angustidens, etc.
This study is based on a compilation of the graptolite faunas from 13 sections that
include all or large portions of the Llandovery (see Fig. 1), and a number of “‘spot’’
outcrops. Four sections, those on Rock River, Tetlit Creek, Blackstone River, and
especially that of the upper canyon of the Peel River, are outstanding with respect to
completeness of sections, high faunal diversity, good exposures, and having been
sampled in detail. They, therefore, form the basis of the present zonal succession.
Glyptograptus persculptus Zone
The definition of the Ordovician-Silurian boundary is at present the subject of
international discussion. Traditionally, the persculptus Zone has been used as the
basal Silurian biostratigraphic unit (Waterlot, 1945; Willefert, 1963; Churkin and
Carter, 1970; Churkin et al., 1971; Hutt, 1975; Bjerreskov, 1975; Rickards, 1976a,
1976b; Rickards, Hutt, and Berry, 1977). Some workers (Munch, 1952; Obut et al.,
1965, 1967; Schauer, 1971) have for practical purposes used the Akidograptus
ascensus-Orthograptus acuminatus Zone (or zones) as the base of the Silurian (see
Koren’ and Kal’o, 1976, for a summary). The persculptus Zone, although not
recognized with certainty in the northern Cordillera, is used as the base of the Silurian
in this study.
Glyptograptus persculptus has not been recognized in the northern Cordillera, but
strata below the acuminatus Zone contain a few diplograptid taxa. The assemblage is
tentatively assigned to the persculptus Zone (see Appendix, Locality 12A).
Orthograptus acuminatus Zone
This zone is readily recognizable in several sections by the appearance of the zonal
index species along with Climacograptus aff. trifilis (which in Germany occurs in the
5
same zone: Munch, 1952; Schauer, 1971) in association with the earliest appearances
of Cystograptus vesiculosus, Diplograptus modestus diminutus, and Orthograptus
oberleint.
Atavograptus atavus Zone
This zone is poorly known in the region, but is marked by the first monograptids in
the Cordilleran region. These are Atavograptus strachani, the most common species,
A. cf. gracilis, and, rarely, A. cf. atavus. Dimorphograptus confertus swanstoni and
D. cf. physophora first appear in this zone, Cystograptus vesiculosus reaches its
acme, and several typical diplograptids continue through this zone.
Lagarograptus acinaces Zone
The zonal designate has been identified from only a few localities, but the recognition
of the zone is on firmer ground than that of the underlying atavus Zone. The zone is
characterized by the influx of abundant, simple monograptids such as Atavograptus
cf. gracilus, A. strachani (reaches its acme in this zone), Pribylograptus spp., as well
as by Dimorphograptus physophora alaskensis, and the common D. confertus
swanstoni.
This zone is correlated with the acinaces Zone of Hutt (1975), Bjerreskov (1975),
and Rickards (1976a), and with the upper part, at least, of the vesiculosus Zone of
Munch (1952), Obut et al. (1965, 1967), and Schauer (1971).
Coronograptus gregarius Zone
This zone is recognized by the incoming and profusion of the coronograptids,
Coronograptus gregarius gregarius, C. g. arcuatus, and C. hipposideros, and the
appearance of M. revolutus. The zone also contains ‘‘Orthograptus”’ obuti, and in a
single collection yielded two specimens of Coronograptus cf. cyphus. The zone is
equivalent to the well-known cyphus Zone of Great Britain (Hutt, 1975; Rickards,
1976a), but is older than the gregarius Zone of Willefert (1963), Schauer (1971), and
Bjerreskov (1975). As such, the zone is in fact the ‘‘acme-zone’’ of C. gregarius and
related species.
Monograptus triangulatus Zone
This zone is not widely recognized in the northern Cordillera, but the zone is
recognized by the incoming of triangulate monograptids such as M. triangulatus and
its subspecies, by Rastrites such as R. approximatus (Rickards, 1976a), as well as by
Lagarograptus inexpeditus and the first appearance of Petalograptus ovatoelongatus .
The zone correlates with part of the gregarius Zone of Sudbury (1958) and Churkin
and Carter (1970), and with at least the triangulatus Subzone of the gregarius Zone of
Bjerreskov (1975).
6
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Diplograptus magnus Zone?
This zone is the poorest documented of the Llandoverian zones of this study. It is
apparently characterized by the lowest occurrence of Monograptus involutus, in
association with Rhaphidograptus cf. toernquisti, and a number of long-ranging
triangulate monograptids, Monograptus revolutus and Pribylograptus angustus. The
index species, Diplograptus magnus, has not yet been found in the Canadian
Cordillera.
Monograptus argenteus Zone
The argenteus Zone, although found only on the Peel and Blackstone rivers, is
readily recognized by the association of Monograptus cf. argenteus, M. aff. cygneus
(sensu Obut and Sobolevskaya, 1967), M. millepeda, and M. communis, as well as
by the earliest occurrences of Petalograptus intermedius and Rastrites orbitus.
The zone is the correlative of the upper part of the gregarius Zone of Churkin and
Carter (1970) and of Bjerreskov (1975), the argenteus Zone of Hutt (1975) and
Rickards (1976a), and the argenteus Subzone of the gregarius Zone of Waterlot
(1945).
Monograptus convolutus Zone
The basis for the recognition of this zone is relatively firm, thanks to its greater
geographic distribution and greater thickness as compared to underlying zones, as
well to its distinctive fauna. Characteristic species of the zone include M. convolutus,
M. sidjachenkoi, M. clingani, Petalograptus folium, and Cephalograptus cometa
cometa and C. tubulariformis.
The convolutus Zone is widely recognized in southeastern Alaska (Churkin and
Carter, 1970), Great Britain (Hutt, 1975; Rickards, 1976a), Germany and
Czechoslovakia (Munch, 1952; Schauer, 1971), Scandinavia (Bjerreskov, 1975),
Morocco (Waterlot, 1945; Willefert, 1963), Poland (Teller, 1969), and several areas
of the USSR (Obut et al., 1965, 1967).
Monograptus sedgwicki Zone
This zone, while not widespread, is well presented in the Peel and Blackstone Rivers
sections. In addition to containing the acme of the index species, the zone contains
Cephalograptus cometa extrema, Monograptus pseudobecki, M. decipiens, and M.
cf. tenuissmus, and documents the earliest appearance of M. spiralis cf. contortus,
Rastrites linnaei, and Pseudoplegmatograptus obesus obesus. The zone is widely
recognized throughout western Europe, Great Britain, Morocco, and the USSR.
Monograptus turriculatus Zone
The turriculatus Zone is readily recognized through the association of M. turriculatus
8
and M. exiguus/M. exiguus primulus. Other guides to the zone include M. marri, M.
flagellaris, Pseudoplegmatograptus obesus reticulatus, Petalograptus altissimus, and
Rastrites maximus. Rastrites linnaei and Monograptus tullbergi spiraloides end and
begin in this zone, respectively.
This zone is, next to the spiralis Zone, the most widespread Llandovery graptolite
zone in the northern Cordillera, and is also recognized in Arctic Canada
(Thorsteinsson, 1958).
The turriculatus Zone, as here used, encompasses the turriculatus Zone of
Rickards (1976a), the linnaei and turriculatus zones of Obut et al. (1965, 1967), and
Schauer (1971), and probably all of the maximus Zone of Churkin and Carter (1970).
Monograptus spiralis Zone
The spiralis Zone is the most ubiquitous and thickest Llandovery zone of the region
(Jackson and Lenz, 1962; Lenz, 1979), and is well known in the Arctic Islands
(Thorsteinsson, 1958; personal observation). It is characterized by an abundance of
Monograptus spiralis in association with the first M. priodon, Retiolites geinitzianus
angustidens, Stomatograptus grandis grandis, and S. grandis imperfectus. The rarer
Monograptus curvus is found in this zone and M. tullbergi spiraloides becomes
extinct.
As discussed by Thorsteinsson (1958), Jackson and Lenz (1962), and Lenz (1979),
the spiralis Zone of northern and Arctic Canada is longer ranging in age than the zone
of that name in Europe, and correlates with the combined crispus and griestoniensis
Zones, and possibly in part with the crenulata Zone of Great Britain (see Rickards,
1976a).
Cyrtograptus sakmaricus-C. laqueus Zone
This zone, defined by Lenz (1979), is marked by the abrupt appearance of
cyrtograptids such as Cyrtograptus sakmaricus, C. laqueus, and C. aff. lapworthi, in
association with Stomatograptus grandis grandis, S. grandis imperfectus, as well as
less common Retiolites geinitzianus angustidens and rare Monograptus spiralis.
The zone is the biostratigraphic correlative of the Cyrtograptus sp. nov.
A-Stomatograptus grandis Zone of Thorsteinsson (1958), the lapworthi Zone of
Bjerreskov (1975), and the Oktavites spiralis-Stomatograptus grandis Zone of Obut
et al. (1965, 1967). It is equivalent, at least in part, to the spiralis spiralis Zone of
Schauer (1971), and probably to the combined M. probosciformis-Stomatograptus
grandis Zone of Munch (1952).
Systematic Palaeontology
Repository
Illustrated graptolite types and specimens are housed in the Department of
Invertebrate Palaeontology, Royal Ontario Museum, Toronto, and are assigned ROM
9
number 38674 to 38986. In this study, abundances of a graptolite species in a
collection is listed as ‘‘rare’’ (1-3), ‘‘uncommon’’ (4-10), “‘common’’ (11-20, and
‘‘abundant’’ (more than 20).
Order Graptoloidea Lapworth, 1875
Suborder Diplograptina Lapworth, 1880, emended Bulman, 1970
Family Diplograptidae Lapworth, 1873
Genus Petalograptus Suess, 1851
Type Species
Prionotus folium Hisinger, 1837, from the Llandovery of Sweden; subsequent
designation Lapworth, 1873.
Petalograptus altissimus Elles and Wood, 1908
Figs: 2A, B; 12A2=C7 ni
Petalograptus altissimus Elles and Wood, 1908: 281.
Petalolithus altissimus, Bouéek and Pribyl, 1941a: 12.
Petalolithus giganteus, Bouéek and Pribyl, 1941a: 18.
Petalolithus conicus, Bouéek and Pribyl, 1941a: 15.
Petalograptus (Pet.) altissimus, Schauer, 1971: 47.
Petalograptus altissimus, Bjerreskov, 1975: 34.
Fig. 2 A,B Petalograptus altissumus Elles and Wood, Blackstone River
A. Collection at 77.2 m, sedgwicki Zone, ROM 38674; x 3.4.
B. Collection at 91.4 m, turriculatus Zone, ROM 38675; x 3.4.
C,D. Petalograptus folium (Hisinger), convolutus Zone
c. Blackstone River, collection at 69.2 m, ROM 38676; x 3.4.
D. Peel River, collection at 498.7 m, ROM 38677; x 3.4.
E-G,1,J,N Petalograptus intermedius (Boucek and Pribyl)
E,F. Blackstone River, collection at 77.2 m, sedgwicki Zone?, ROM 38678 and
38679; x 3.4.
G,l. Blackstone River, collection at 65.5 m, argenteus Zone?, ROM 38680 and
38681; x 3.4.
J. Peel River, collection at 498.7 m, convolutus Zone, ROM 38682; x 3.4.
N. Peel River, collection at 487.4 m, triangulatus Zone, ROM 38683; x 6.
H,O. Petalograptus cf. palmeus palmeus (Barrande), Peel River, collection at 523 m,
turriculatus Zone, ROM 38684 and 38685; x 3.4.
K-M. Petalograptus ovatoelongatus (Kurck), Peel River, turriculatus Zone
K. Collection at 521.8 m ROM 38686; x 3.4.
L. Collection at 523 m, ROM 38687; x 3.4.
M. Collection at 516.3 m, ROM 38688; x 3.4.
P. Petalograptus cf. palmeus praecedens (Bouéek and Pribyl), Peel River, collection at
512.8 m, convolutus Zone, ROM 38689; x 3.4.
10
Occurrence
Sedgwicki Zone, Blackstone River, at 72.2 m and tentatively at 77.2 m; turriculatus
Zone, Peel River at 521.8 and 531.9 m, and tentatively 523 m; Blackstone River, at
91.4 m and tentatively from 80.2 m.
Material
Relatively rare as fairly to moderately well-preserved carbon films on black shale.
Illustrated specimens are ROM 38674, 38675, 38845 to 38847, and 38850.
Description
The rhabdosome of this species may be as much as 20mm long, and
characteristically undergoes gradual widening from 1.1 to 1.3 mm across theca 1, to
a maximum of 3 to 3.5 mm. Only at the distal end of long specimens does the width
decrease slightly. The thecae are simple tubes distally inclined about 70 degrees to the
virgula, overlap about two-thirds their length distally, are about four times longer
than wide, and number 13 to 16 in 10 mm proximally and 11 to 12 in 10 mm distally.
A stout virgula may be present in the distal half of the rhabdosome.
Discussion
Canadian specimens of the species, like those of Bjerreskov (1975) from Denmark,
possess more thecae than is typical for British and Czech specimens. The narrow
proximal end, the slow widening of the rhabdosome, and the conical outline are
typical of this species.
Petalograptus elongatus (Boucek and Pribyl, 1941)
Figss 1 5B), G
Petalolithus elongatus elongatus Boucek and Pribyl, 1941a: 10.
Petalolithus elongatus, Munch, 1952: 62.
Petalolithus (Pet.) elongatus, Schauer, 1971: 46.
Occurrence
Sedgwicki and turriculatus zones, Peel River, at 513.6 m; Rock River, at 287 m; and
Blackstone River, at 72.2, 77.2, and 88.7 m, and tentatively from 80.2, 85.3, 86.9,
and 91.4 m.
Material
An average of eight specimens from each collection, all flattened, moderately well to
well preserved. Illustrated specimens consist of ROM 38856 to 38858.
12
Description
The rhabdosome is up to 25 mm long and is essentially parallel-sided. The proximal
end is 0.9 to 1.1 mm wide across theca 1 and width increases rapidly for the distance
of 5 to 6 thecae, then remains constant. Width is variable, ranging from 1.5 mm to
2.1 mm, but averaging 2.0 mm. The sicula is 1.4 to 1.5 mm long, its apical end
attaining the level of the top of theca 2 and it possesses a short virgella.
The thecae are straight and tubelike, inclined about 30 degrees, overlap one-half
their length distally, are two to two and one-half times longer than wide distally, and
number 12 to 10 in 10 mm. Thecal apertures are slightly curved, and form an angle of
90 degrees to 110 degrees to the theca! axis.
A spiralled, vanelike virgula extends well beyond the distal end of the rhabdosome
of some specimens.
Discussion
This species is distinguished from the very similar P. tenuis by its longer sicula. The
sicula in the Yukon specimens is shorter than the 2 mm cited by Schauer (1971) for
this species and is midway between that of the typical P. tenuis and P. elongatus,
raising the possibility that the two are conspecific, or at best subspecies of the same
species.
Petalograptus folium (Hisinger, 1837)
Pigss 26) 0351250).
Prionotus folium Hisinger, 1837: 114.
Petalograptus folium, Elles and Wood, 1908: 282.
Petalolithus folium, Boucek and Pribyl, 1941b: 7.
Petalolithus (Pet.) folium, Schauer, 1971: 41.
Petalograptus folium, Bjerreskov, 1975: 35.
Petalolithus folium, Ni, 1978: pl. 2.
Petalolithus folius, Chen and Lin, 1978: 44.
Occurrence
Convolutus Zone, Peel River, at 496.2 and 498.7 m, and Blackstone River, at 66.4
and 69.2 m.
Material
Relatively uncommon in all collections except Blackstone River at 69.2 m, from
which 22 specimens were recovered. All specimens are fairly well preserved but most
are incomplete. Illustrated specimens are ROM 38676 to 38677 and 38848 to 38849.
Description
The rhabdosome is up to 2 cm long, tapering and snoutlike proximally, widening
slowly from 2.7 to 3.8 mm across theca 1, to a maximum of 4.8 to 6.0 mm (average
5.2 mm) distally. The sicula is robust and 2.0 to 2.1 mm long.
The thecae are about eight times longer than wide, inclined 20 to 30 degrees
throughout, overlap eight- or nine-tenths of their length and number 9 to 11 in 10 mm
proximally and 9 in 10 mm distally. Theca 1 is about 4.5 mm long, whereas distal
thecae are about 5.5 mm long. The virgula is threadlike proximally, but may become
stout in distal parts of the rhabdosome, and beyond the main body.
Discussion
The cone-shaped proximal end and long proximal thecae are typical of this species
and serve to distinguish it from other species.
Petalograptus cf. hispanicus Haberfelner, 1931
Fig. 12G
cf. Petalograptus hispanicus Haberfelner, 1931: 49.
Bigs SA-e.
14
K,N.
L,M,O.
S-U.
Cephalograptus cometa cometa (Geinitz), Blackstone River, collection at 70.4 m,
convolutus Zone, ROM 38690, 38691, and 38692: all x 3.4.
Cephalograptus cometa extrema Bouéek and Pribyl, Blackstone River, collection at
77.2 m, sedgwicki Zone, ROM 38693; x 3.4.
. Cephalograptus tubulariformis (Nicholson) Blackstone River, collection at 69.2 m,
convolutus Zone, ROM 38694 and 38695; x 6.8 and x 3.4.
. Dimorphograptus confertus swanstoni Lapworth
G.J. Peel River, collection at 460 m, acinaces Zone, ROM 38696 and 38697; x 6.8
and X 3.4.
H. Blackstone River, collection at 62.2 m, atavus Zone?, ROM 38698; x 3.4.
1. Peel River, collection at 463 m, gregarius Zone, ROM 38699; x 3.4.
Dimorphograptus cf. physophora (Nicholson)
K. Rock River, collection at 244 m, gregarius Zone, ROM 38700; x 4.
N. Blackstone River, collection at 61.9 m, atavus Zone?, ROM 38701; x 3.4.
Dimorphograptus physophora alaskensis Churkin and Carter
L,O. Rock River, collection at 244 m, gregarius Zone, ROM 38702 and 38703; x 4.
M. Pat Lake, collection 3F, acinaces Zone, ROM 38704; x 6.8.
Rhaphidograptus sp., Pat Lake, Collection 3F, acinaces Zone, ROM 38705; x 6.8.
Rhaphidograptus cf. toernquisti (Elles and Wood), Peel River, collection at 485.9 m,
magnus Zone?, ROM 38706; x 6.8.
Barrandeograptus aff. pulchellus (Tullberg), Blackstone River, collection at 72.2 m,
sedgwicki Zone, ROM 38707; xX 3.4.
?Diversograptus ramosus Manck
S. Rock River, collection 9F, spiralis Zone, ROM 38708; x 6.8.
T,U. Peel River, collection at 630.9 m, sakmaricus-laqueus Zone, ROM 38709;
x 3.4 and x 6.8.
Occurrence
Turriculatus Zone, Peel River, at 544.4 m; Blackstone River, at 94.8 m; Tetlit Creek,
at 144 m; and Clearwater Creek, at 65.5 m.
Material
Only a few poorly to moderately well-preserved, flattened specimens are available
from each collection. Illustrated specimen is ROM 38856.
Discussion
The few specimens tentatively assigned to this species rather resemble dwarfed P.
altissimus , but are clearly distinguished by being much narrower. The proximal end is
long and tapering, the maximum width attained is 2.2 to 2.8 mm, and thecae number
12 to 14 in 10 mm proximally and 10 to 12 in 10 mm distally. The sicula, seen in only
one specimen, appears to be about 1.5 mm long.
Petalograptus intermedius (Bouéek and Pribyl, 1941)
Figs. 2E-G,1,J,N; 12F, I-L
Petalolithus intermedius Boucek and Pribyl, 1941b: 10.
Petalolithus primulus Boucek and Pribyl, 1941b: 6.
Petalolithus praecursor Boucek and Pribyl, 1941b: 10.
Petalolithus (Pet.) intermedius, Schauer, 1971: 41.
Occurrence
This is a long-ranging species, ranging through the triangulatus, argenteus,
convolutus, and turriculatus zones. Peel River, at 487.4 m and tentatively at 498.7,
506.3, and 508.4 m; and Blackstone River, at 65.5, 70.4, 72.2, 74.7, 77.2, and
80.2 m.
Material
The species is relatively rare to uncommon in most collections, but is very abundant
and dominant in collections from the Blackstone River, particularly in that made at
77.2 m. Preservation is fair to good, and many specimens preserve an external
virgula. Illustrated specimens are ROM 38678 to 38683, 38851 to 38853, and 38855.
Description
The rhabdosome is typically ovate-elongate in outline, although a few large
16
specimens maintain more or less consistent width for about two-thirds the length. The
proximal region is narrow and maximum width is attained rapidly within the distance
of the first four to six thecae; distally, most rhabdosomes decrease in width.
Maximum width ranges from 3.5 to 5.1 mm.
The thecae are straight and tubelike, except that their distal ends are flexed
outwardly to form a lip. The thecae are inclined 30 to 40 degrees and distal thecae are
about four times longer than wide. Thecae number 14 to 12 in 10 mm proximally and
10 to 12 in 10 mm distally. The sicula is 1.5 to 1.8 mm long.
Discussion
The width of this species varies considerably, even in specimens from the same
collection. In one collection (Blackstone River, at 77.2 m), the width ranges from 3.6
to 5.1 m. The species is distinguished from P. palmeus palmeus by its consistently
greater width, and from P. p. clavatus by its ovate outline.
Petalograptus ovatoelongatus (Kurck, 1882)
Figs. 2K=Me 13 A. Cc, H
Cephalograptus ovato-elongatus Kurck, 1882: 303.
Petalograptus palmeus var. ovato-elongatus, Elles and Wood, 1908: 277.
Petalolithus ovato-elongatus, Boucek and Pribyl, 1941b: 2.
Petalolithus (Pet.) ovatoelongatus, Schauer, 1971: 40.
Petalograptus ovatoelongatus, Bjerreskov, 1975: 32.
Petalograptus ovatoelongatus, Hutt, 1975: 39.
Occurrence
Argenteus, convolutus?, and turriculatus zones; Peel River collections, at 491.4,
516.3, 521.8, and 523 m; and Blackstone River, at 65.5 m, and tentatively at
88.7 m.
Material
Rare in any collection, but mostly well preserved as a carbon film on black shale.
Illustrated specimens are ROM 38686 to 38688.
Description
The rhabdosome is robust and may attain lengths greater than 2 cm. The proximal
end is ovate, and width increases very rapidly from an initial 3 to 4mm to a
maximum of 4.5 to 6.0 mm by thecae 4 to 6. The width thereafter decreases
gradually to 3 to 4 mm. The sicula is 1.5 to 2.0 mm in length.
The proximal thecae are strongly curved outward and distal ends of the thecae
subtend an angle of 70 to 90 degrees to the virgula. Distal thecae are gently curved
and are inclined about 20 to 30 degrees to the virgula. The thecae number 12 to 13 in
10 mm proximally and 10 to 12 in 10 mm distally.
The virgula may be hairlike, or (rarely), robust.
Discussion
Canadian representatives of this species differ from the European specimens only in
possessing slightly more widely spaced thecae and in being wider. The abrupt
proximal widening and the gently tapered aspect of the distal portion of the
rhabdosome are distinctive of the species.
Petalograptus cf. palmeus palmeus (Barrande, 1850)
Figs: 2H, ©; 13F, 1
cf. Graptolithus palmeus Barrande, 1850: 61.
Occurrence
Turriculatus Zone of Peel River, at 516.9, 518.8, and 523 m.
Material
Two well-preserved, and eight incomplete, poorly preserved specimens from 516.9
and 518.8 m, and three specimens from 523 m, flattened on black shale. Illustrated
specimens are ROM 38684 to 38685 and 38860 to 38861.
Fig. 4 A,.B,L. Atavograptus cf. gracilis Hutt, Peel River, collection at 461.5 m, acinaces Zone, ROM
38710, 38711, and 38712; all x 6.8.
C,M,N. Lagarograptus inexpeditus Obut and Sobolevskaya, Peel River, collection at
481.9 m, triangulatus Zone?, ROM 38726 and 38727; both x 6.8.
D,E,0,Q. Coronograptus gregarius gregarius (Lapworth)
D. Rock River, collection at 254 m, gregarius Zone, ROM 38713; x 8.
E. Peel River, collection at 488 m, magnus Zone?, ROM 38714; X 6.8.
0,Q. Peel River, collection at 465.1 m, gregarius Zone, ROM 38715 and 38716;
bothx 6.8.
F. Coronograptus cf. cyphus (Lapworth), Rock River, collection at 255 m, gregarius
Zone, ROM 38717; x 8.
G,H,P. Lagarograptus cf. acinaces (Tornquist), Rock River, gregarius Zone
G. Collection at 245 m, ROM 38718; x 8.
H. Collection at 249 m, ROM 38719; x 4.
P. Collection at 254 m, ROM 38720; x 8.
IJ,K,R,S. Atavograptus strachani (Hutt and Rickards), acinaces Zone
|. Blackstone River, collection at 62.5 m, ROM 38721; x 6.8.
JK. Tetlit Creek, collection at 133 m, ROM 38722 and 38723; both x 4.
R,S. Peel River, collection at 460 m, ROM 38724 and 38725; both x 3.4.
Description
The rhabdosome is weakly ovate, widening moderately rapidly from an initial width
of 1.0 mm through the distance of the first three thecae, then gradually to a maximum
width of 3.0 to 3.4 mm, which is attained about midlength. The longest specimen is
15 mm. The sicula is about 1.4 mm long.
The proximal thecae are short and moderately outwardly curved, whereas distal
thecae are only gently curved, form an angle of 30 to 40 degrees with the virgula, and
are about four times longer than wide. The thecae number 14 to 15 in 10 mm
proximally and 12 in 10 mm distally.
Discussion
The study material differs from the typical specimens in possessing relatively more
thecae, although the spacing is the same as that described by Bjerreskov (1975). It
differs from P. palmeus of Churkin and Carter (1970) in being considerably larger.
Petalograptus cf. palmeus clavatus (Boucéek and Pribyl, 1941)
Fig. 13E
cf. Petalolithus palmeus clavatus Boucek and Pribyl, 1941: 6.
Occurrence
From the turriculatus Zone of Peel River, 518.8 m.
Material
Two specimens, one well preserved, carbon films on black shale. Illustrated
specimen is ROM 38859.
Discussion
The two specimens, although associated with P. cf. palmeus palmeus, differ
strikingly from that species. They widen abruptly from an initial width of about
2.0 mm to a maximum distal width of 3.5 mm in the distance of three to four thecae,
then taper gradually to a distal width of 2.3 mm. The sicula is 1.4 mm long. The
proximal thecae are sharply curved so that their apertures are parallel to the
rhabdosome axis, whereas the distal thecal apertures are inclined at a low angle to the
axis, and form an obtuse angle with the thecal axis. The thecae number 13 in 10 mm
proximally and 11 in 10 mm distally. A long external virgula with a twirled, vanelike
structure is present (the ‘‘simple’’ vincular type of Schauer, 1971: 38, fig. 20).
20
This form may be an anomalous morphotype of P. palmeus palmeus, but because
of its abrupt widening, and distally tapering rhabdosome, is tentatively assigned to P.
p. clavatus.
Petalograptus cf. palmeus praecedens (Boucek and Pribyl, 1941)
Fig. 2P
cf. Petalolithus praecedens Boucek and Pribyl, 1941: 8.
?Petalograptus palmeus (Barrande), Churkin and Carter, 1970: 32.
Occurrence
Convolutus Zone of Peel River, at 512.8 m.
Material
Four specimens, two moderately well preserved, all flattened on black shale.
Illustrated specimen is ROM 38689.
Discussion
This subspecies is distinguished from the typical species in being shorter (maximum
length about 1 cm), and narrower (maximum width observed 2.3 mm). Otherwise it is
typical of the palmeus group. The sicula is 1.3 to 1.4 mm long and the thecae number
about 13 in 10 mm. The Yukon material appears to be almost indistinguishable from
the P. palmeus of Churkin and Carter (1970) from southeastern Alaska, where it in
part has the same stratigraphic range.
Genus Cephalograptus Hopkinson, 1869
Type Species
Diplograptus cometa Geinitz 1852, from the Llandovery of Germany; original
designation.
Cephalograptus cometa cometa (Geinitz, 1852)
Pigs, 3A-C; 14A-¢
Diplograptus cometa Geinitz, 1852: 26.
Cephalograptus cometa, Elles and Wood, 1908: 285.
21
Cephalograptus cometa cometa, Boucek and Pribyl, 1941b: 13.
Petalolithus (Ceph.) cometa cometa, Schauer, 1971: 49.
Cephalograptus cometa cometa, Bjerreskov, 1975: 36.
Occurrence
Upper part of the convolutus Zone, Blackstone River, at 70.4 m.
Material
Eleven specimens, several moderately well preserved although flattened on black
shale. Illustrated specimens consist of ROM 38690 to 38692 and 38862 to 38863.
Description
The rhabdosome is elongate with a long, narrow, cone-shaped proximal end and an
anteriorly rounded distal end. Maximum width of 3.0 mm is attained immediately
across the level of the aperture of the first thecae; thereafter, width may remain
constant for the distance of the next several thecae, or, more commonly, begins
decreasing. The sicula was not seen, but some specimens possess a slightly wider,
bulbous end.
The proximal thecae are very elongate (about 10 mm long), inclined at a very low
Fig.5 A,B,E. Coronograptus hipposideros (Toghill), Peel River, collection at 471.5 m, gregarius
Zone, ROM 38728, 38729, and 38730; all x 6.8.
C,D,R. Coronograptus gregarius arcuatus Obut and Sobolevskaya, gregarius Zone
c. Peel River, collection at 470.3 m, ROM 38731; x 6.8.
D. Tetlit Creek, collection at 136 m, ROM 38732; x 4
R. Peel River, collection at 475.5 m, ROM 38733; x 3.4.
F,G,T. Monograptus communis Lapworth, Peel River, collection at 496.2 m, convolutus
Zone, ROM 38734, 38735, and 38736; all x 3.4.
HJ. Pristiograptus regularis (Tornquist), Peel River
H. Collection at 519.4 m, sedgwicki Zone? ROM 38737; x 3.4.
1. Collection at 523 m, turriculatus Zone, ROM 38738; X 3.4.
J. Collection at 521.8 m, turriculatus Zone, ROM 38739; x 3.4.
K,N,O. Pristiograptus cf. variabilis (Perner), Peel River, collection at 523 m, turriculatus
Zone, ROM 38740, 38741, and 38742; all x 3.4.
L,M,P. Pristiograptus nudus (Lapworth)
L. Peel River, collection at 523 m, turriculatus Zone, ROM 38743; x 3.4.
M. Blackstone River, collection at 72.2 m, sedgwicki Zone, ROM 38744; x 3.4.
P. Blackstone River, collection at 70.4 m, convolutus Zone, ROM 38745; x 3.4.
Q. Pribylograptus angustus (Rickards), Peel River, collection at 488 m, magnus Zone?,
ROM 38746; x 6.8.
S. Monograptus cf. argenteus (Nicholson), Peel River, collection at 491.4 m, argenteus
Zone, ROM 38747; x 3.4.
U,V. Monograptus clingani (Carruthers), Peel River, convolutus Zone
U. Collection at 507.8 m, ROM 38748; x 3.4.
Vv. Collection at 498.7 m, ROM 38749; x 3.4.
jp
angle to the rhabdosome axis; distal thecae are shorter and inclined at 10 to 15
degrees. In the largest specimen, seven thecae are observed. Thecae number 8 in
10 mm.
Cephalograptus cometa extrema Boucek and Pribyl, 1941
Figs. 3D; 14G, H
Cephalograptus cometa, Elles and Wood, 1908: 285.
Cephalograptus cometa extrema, Boucek and Pribyl, 1941b: 14.
Petalolithus (Ceph.) cometa extrema, Schauer, 1971: 50.
Cephalograptus cometa extrema, Bjerreskov, 1975: 37.
Occurrence
Sedgwicki Zone of Blackstone River, at 77.2 m.
Material
Seven specimens, poorly to moderately well preserved on black shale. Illustrated
specimens are ROM 38693 and 38869.
Description
The rhabdosome is very slender, reaching a maximum length of 16mm. The
maximum width is 1.4 to 1.5 mm which is attained immediately at the level of the
aperture of theca 1; thereafter the rhabdosome narrows rapidly. The greatest number
of thecae is three. A sicula was not observed.
The thecae are also very long and slender, and the first theca appears to exceed
12 mm in length, whereas distal thecae shorten markedly. The thecae are inclinded 2
to 4 degrees and overlap almost their entire length.
Discussion
C. cometa extrema is the most extremely elongated and the stratigraphically highest
form of the C. tubulariformis-C. cometa cometa-C. cometa extrema lineage. These
three species appear to be useful for precise correlation.
Cephalograptus tubulariformis (Nicholson, 1867)
Figs. 3E-F; 14E
Diplograptus tubulariformis Nicholson, 1867: 111.
Cephalograptus tubulariformis, Elles and Wood, 1908: 287.
24
Cephalograptus tubulariformis, Bouéek and Pribyl, 1941b: 12.
Petalolithus (Ceph.) tubulariformis, Schauer, 1971: 49.
Cephalograptus tubulariformis, Bjerreskov, 1975: 36.
Occurrence
Convolutus Zone, Blackstone River, at 69.2 m.
Material
Seven specimens, three of which are moderately well-preserved, on black shale.
Illustrated specimens are ROM 38694 to 38695.
Description
The rhabdosome is wedge shaped, the proximal end being narrow and cone shaped,
the distal end being more or less parallel-sided. The maximum width attained is
4.2 to 5 mm, whereas the width across the first theca is 3.0 mm. The sicula was not
seen.
The proximal thecae are simple, gently curved tubes, inclined about 20 degrees to
the virgula and they are spaced at eight to nine in 10 mm. The initial theca appears to
be about 5 mm or more in length. Distal thecae are shorter than proximal thecae and
are inclined about 30 degrees.
Discussion
The Canadian material is similar to specimens of the species previously described
from Europe, and differs only in possessing a slightly more protracted and more
sharply pointed proximal end. Its morphology and stratigraphic position supports
Rickard’s et al. (1977) suggestion that it is ancestral to C. cometa cometa.
Family Dimorphograptidae Elles and Wood, 1908
Genus Dimorphograptus Lapworth, 1876
Type Species
Dimorphograptus elongatus Lapworth, from the Llandovery of Scotland; subsequent
designation Bassler, 1915.
Dimorphograptus confertus swanstoni Lapworth, 1876
Fios3G-);, 15.A,B
Dimorphograptus Swanstoni Lapworth, 1876: 548.
25
Dimorphograptus confertus var. Swanstoni, Elles and Wood, 1908: 350.
Dimorphograptus swanstoni, Obut and Solobevskaya, 1967: 72.
Dimorphograptus confertus swanstoni, Churkin and Carter, 1970: 33.
Dimorphograptus confertus swanstoni, Churkin et al., 1971: 24.
Dimorphograptus confertus swanstoni, Schauer, 1971: 52.
Occurrence
Atavus? and acinaces zones, Peel River, at 459.6, 460, 460.6, 461.5, 463, and
465.1 m; and Blackstone River, at 62.2 m.
Material
Five to ten incomplete and moderately well-preserved specimens from each
collection. Illustrated specimens are ROM 38696 to 38699 and 38870.
Description
The rhabdosome is up to 30 mm long, and is straight except for the uniserial portion
which generally shows weak dorsal curvature. The rhabdosome widens gradually
from 1.5 to 1.7 mm across the first biserial thecae to a maximum of 2.1 to 2.6 mm
(average 2.4 mm) distally. The uniserial portion is composed of five to six more or
less climacograptid thecae, whereas those of the biserial portion are orthograptid to
glyptograptid. The thecal walls of the biserial portion are sigmoidal and often
lip-bearing; the apertures, which undulate, are inclined about 90 degrees to the
virgula. Thecae number nine to ten in 10 mm in the uniserial portion and eight to nine
in 10 mm in the biserial. The sicula is robust and 1.9 to 2.3 mm (average 2.0 mm) in
length.
Fig. 6 A.C. Monograptus curvus Manck, Peel River, collection at 611.4 m, spiralis Zone, ROM
38750 and 38751; both x 3.4.
B. Monograptus convolutus (Hisinger), Peel River, collection at 498.7 m, convolutus
Zone, ROM 38752; x 3.4.
D,E. Monograptus aff. cygneus Tornquist (sensu Obut and Sobolevskaya, 1967), Peel
River
D. Collection at 512.8 m, convolutus Zone, ROM 38753; X 3.4.
E. Collection at 491.4 m, argenteus Zone, ROM 38754; x 3.4.
FN. Monograptus decipiens decipiens Tornquist, Peel River, collection at 526 m,
turriculatus Zone, ROM 38755 and 38756; both x 3.4.
G,J,L. Monograptus decipiens valens (Pribyl and Minch), turriculatus Zone
G. Peel River, collection at 518.8 m, ROM 38757; x 3.4.
J. Peel River, collection at 521.8 m, ROM 38758; x 3.4.
L. Blackstone River, collection at 88.7 m, ROM 38759; x 3.4.
H,I,K. Monograptus cf. denticulatus Tornquist, Peel River, collection at 519.4 m, sedgwicki
Zone?, ROM 38760, 38761, and 38762; all x 3.4.
M.P. Monograptus crispus Lapworth, Ellesmere Island, crispus Zone? (= spiralis Zone),
ROM 38763 and 38764; both x 6.8.
0. Monograptus cf. elongatus Tornquist, Peel River, collection at 477 m, triangulatus
Zone, ROM 38765; x 6.8.
Zi
Discussion
Yukon specimens of this species are similar in all respects to those from Britain, as
well as to those from Alaska illustrated by Churkin and Carter (1970). They differ
from the illustrated specimens of Obut et al. (1967) in possessing a longer sicula.
Dimorphograptus cf. physophora (Nicholson, 1868)
Figs. 3K, N; 15D, E
cf. Diplograptus physophora Nicholson, 1868: 56.
Occurrence
Atavus? Zone, Blackstone River, at 61.9 m; and from the gregarius Zone, Rock
River, at 244 m, and Tetlit Creek, at 136 m.
Material
A single, moderately well-preserved, flattened specimen from each of Blackstone and
Rock rivers, and six incomplete specimens from Tetlit Creek. Illustrated specimens
are ROM 38700 to 38701 and 38873 to 38874.
Description
The rhabdosome is longer than 25 mn, is straight, and ranges in width from 1.5 mm
across theca 1, to a maximum of 2.5 mm, width increase is very gradual. The
uniserial portion is short, less than 2 mm long, and bears two glyptograptid thecae,
theca 1 being 1 mm long. The distal thecae are all glyptograptid in profile, inclined
about 30 degrees to the virgula, overlap about one-half, and their apertures are
straight and at right angles to the virgula. Thecae number 10 to 11 in 10 mm
proximally and 8 in 10 mm distally. The sicula is not clearly discernible, but appears
to be about 1.8 mm long and possesses a stout, virgellar spine. A faint proximal
disclike body and lateral, weblike strands are seen in the specimen from Rock River.
Discussion
The uniserial portion of the single specimen from Blackstone River is longer than is
typical for D. physophora. It differs from D. longissimus in possessing a distinctly
shorter uniserial portion. The study specimens are most similar to D. physophora in
the nature of their glyptograptid thecae.
28
Dimorphograptus physophora alaskensis Churkin and Carter, 1970
Figs. 3L,M,O; 14F, I-K
Dimorphograptus physophora alaskensis Churkin and Carter, 1970: 33.
Occurrence
Acinaces and gregarius zones, Blackstone River, at 62.5 m; Rock River, at 244 m;
and Pat Lake, collection 3F.
Material
Thirteen specimens, of which seven are from Pat Lake. All are flattened on black
shale, and are poorly to moderately well preserved. Illustrated specimens are ROM
38702 to 38704, and 38865 to 38868.
Description
The rhabdosome is as much as 30 mm long. Some specimens attain maximum width
almost immediately, whereas others widen slightly, distal of the initial thecae. Most
specimens range between 2.4 to 2.6 mm in width, but two specimens are 3.4 mm
wide. The sicula is straight, almost completely exposed on one side and 1.6 to
1.7 mm long. The uniserial portion is straight and possesses only a single theca.
The thecae are orthograptid in outline, and vary from a straight outer wall to
curving outwards and forming a lip; they overlap one-half to two-thirds their length,
and number 12 to 13 in 10 mm proximally and 8 to 10 in 10 mm distally. The thecal
apertures are undulose and generally form an obtuse angle with the virgula.
Some specimens possess a proximal ovate web or disclike structure; others possess
only a meshworklike structure, while still others are devoid of any extraneous
structures.
Discussion
The Yukon specimens differ from those of Churkin and Carter’s (1970) species in
being wider and in that some specimens possess a disc or weblike structure. This
structure is more typical of D. physophora physophora; however the Yukon material
differs from that species in possessing more closely spaced thecae and in being
considerably wider.
Some specimens of D. physophora alaskensis bear a strong similarity to
Orthograptus obuti (Rickards and Koren’, 1974), and some specimens with short
uniserial sections and a virgellar meshwork may be that species. Rickards and Koren’
(1974) pointed out the similarity between O. obuti and D. physophora, distinguishing
them by the fact of the greater width and meshwork development in the former
species. In view of the relatively poor preservation of the few Yukon specimens
29
bearing the meshwork, and of the possession of a short uniserial portion in all
specimens, they are tentatively assigned to Churkin and Carter’s (1970) subspecies.
Genus Rhaphidograptus Bulman, 1936
Type Species
Climacograptus Tornquisti Elles and Wood (1906) from the Llandovery of Scotland;
original designation.
Rhaphidograptus sp.
Fig: 3P
Occurrence
Acinaces Zone, Pat Lake, collection 3F.
Material
One specimen, moderately preserved on black shale. The illustrated specimen is ROM
38705.
Discussion
This species appears to differ from the species described herein as R. cf. toernquisti
by being more tapered proximally and possessing thecae which are midway between
typical climacograptid and glyptograptid profiles.
Fig. 7 A.D.F,G. Monograptus exiguus primulus Bouéek and Pribyl, Peel River, turriculatus Zone
A,D. Collection at 536.1 m, ROM 38766 and 38767; x 3.4.
F. Collection at 548.9 m, ROM 38768; x 6.8.
G. Collection at 531.9 m, ROM 38769; x 6.8.
B,C. Monograptus involutus Lapworth, Peel River
B. Collection at 488 m, magnus Zone?, ROM 38770; x 6.8.
C. Collection at 487.4 m, triangulatus Zone, ROM 38771; xX 3.4.
E. Monograptus flagellaris Tornquist, Blackstone River, collection about 91.4 m,
turriculatus Zone, ROM 38772; X 6.8.
H,L. Monograptus planus (Barrande), Peel River, collection at 523 m, turriculatus Zone,
ROM 38773 and 38774; x 3.4 and x 6.8.
I,J. Monograptus lobiferus harpago Tornquist, Peel River, collection at 502.3 m,
convolutus Zone, ROM 38775 and 38776; both x 3.4.
K. Monograptus cf. knockensis Elles and Wood, Blackstone River, collection at 80.2 m,
turriculatus Zone, ROM 38777; X 6.8.
M,O. Monograptus millepeda (M’Coy), argenteus Zone
M. Peel River, collection at 491.4 m, ROM 38778; x 3.4.
oO. Blackstone River, collection at 65.5 m, ROM 38779; x 3.4.
N.P,Q. Monograptus falx (Suess), Peel River
N,P. Collection at 611.4 m, spiralis Zone, ROM 38780 and 38781; x 6.8 and x 3.4
respectively
Q. Collection at 544.4 m, turriculatus Zone, ROM 38782: x 3.4.
30
Rhaphidograptus cf. toernquisti (Elles and Wood, 1906)
Figs. 3Q; 14D
cf. Climacograptus Tornquisti Elles and Wood, 1906: 190.
Occurrence
Magnus? Zone, Peel River, at 485.9 m.
Material
Two incomplete and moderately well-preserved specimens on black shale. Illustrated
specimens ROM 38706 and 38864.
Description
The rhabdosome is incomplete and at least 5.5 mm in length. Width increases from
0.7 mm across theca 1, to a maximum of 1.4 mm. The sicula is not clearly
discernible, but appears to be about 1.5 mm long and, except for its apex, is
completely exposed on one side; it possesses a long virgellar spine.
The thecae are climacograptid and overlap about one-half their length. The thecal
apertures are slightly inwardly inclined. Thecae number about 12 in 10 mm.
Discussion
Although the study specimens are similar to R. toernquisti they are too incomplete for
accurate identification.
Family Retiolitidae Lapworth, 1873
Genus Retiolites Barrande, 1850
Type Species
Gladiolites Geinitzianus Barrande, 1850, from the Llandovery of Czechoslovakia,
original designation.
Retiolites decurtatus Boucéek and Minch, 1943
Figs JSF
Retiolites (Pseudoretiolites ) decurtatus Bouéek and Minch, 1943: 30.
Pseudoretiolites decurtatus, Munch, 1952: 74.
32
Occurrence
Convolutus Zone, Blackstone River, at 66.4 m.
Material
A single complete specimen, of only fair preservation preserved as a carbon film on
black shale. The illustrated specimen is ROM 38875.
Description
The rhabdosome is 15 mm long, ovate in outline, and attains a maximum width of
5.3 mm about midlength. The sicula is not visible. A weak virgula extends through
the length of the specimen. |
The thecae are essentially tubelike, inclined about 60 degrees to the virgula, about
six times longer than wide, possess simple apertures which are perpendicular to the
thecal axis, and number 13 in 10 mm proximally and 11 in 10 mm distally. The entire
rhabdosome is covered with a fine meshworklike reticulum, apparently without a
distinct pattern in the median region of the rhabdosome, but more or less aligned
parallel to the thecal apertures near the apertures. The meshwork of the reticulum is
spaced at the rate of nine in the space of 1 mm.
Discussion
The species differs from R. perlatus, the only similar species, in being narrower and
considerably shorter, and in possessing more closely spaced thecae. The Blackstone
River occurrence of the species in the convolutus Zone is considerably older than its
occurrence in Europe where it is found in the turriculatus Zone (Boucek and Munch,
1943; Munch, 1952).
Retiolites geinitzianus angustidens Elles and Wood, 1908
Figwets¢) Hi
Retiolites (Gladiograptus) Geinitzianus var. angustidens Elles and Wood, 1908: 338.
Retiolites (Retiolites) geinitzianus angustidens, Boucek and Munch, 1943: 37
Retiolites (Ret.) geinitzianus angustidens, Schauer, 1971: 83.
Retiolites geinitzianus angustidens, Bjerreskov, 1975: 38.
Occurrence
Spiralis and sakmaricus-laqueus zones. The species is ubiquitous, and was found at
the following stratigraphic localities: Peel River, at 615.7, 629.4, 630.9, and
33
635.5 m; Tetlit Creek,-at.182. 185, 192.213, 215). 217,.219,and 220.maRockiRaver,
at 323 m; Rock River main tributary in coilections 1F and 3F; Mount Sekwi, at 413
m; Whittaker Range, at 728.5 and 855.6 m; Delorme Range, at 911.4 and 986 m. The
Species is also common in the spiralis Zone of northern Cornwallis Island and
southern Baillie-Hamilton Island, central Arctic Archipelago.
Material
Relatively uncommon in any one collection. Preservation ranges from poor to good,
and all specimens are flattened on black shale. Illustrated specimens are ROM 38871
to 38872.
Description
The rhabdosome is 3 to 4 cm long; it increases in width from about 1.5 mm across
theca | to a maximum of 2.5 to 3.5 mm in about 2 cm, thereafter the width remains
constant. The clathria is well developed and lateral branches alternate regularly on
either side of the central straight or zigzag line. The virgula is present throughout the
length of the rhabdosome.
The thecae are essentially simple, parallel-sided tubes which overlap throughout
their lengths; they are inclined about 45 degrees to the virgula, are rectangular in
cross-section, and number 14 in 10 mm proximally and 9 to 10 in 10 mm distally.
The clathria is covered by a reticulum in which meshes are more or less quadrate in
outline and number four to five in 1 mm in the distal part of the rhabdosome.
Fig. 8. A. Monograptus minimus Bouéek and Pribyl, Rock River, main branch, collection 4F,
sakmaricus-laqueus Zone, ROM 38783; Xx 6.8.
B,C. Monograptus cf. pandus Lapworth, Peel River, collection at 544.4 m, turriculatus
Zone, ROM 38784 and 38785; x 3.4.
D,E. Monograptus marri Perner, Peel River, collection at 548.9 m, turriculatus Zone, ROM
38786 and 38787; x 3.4 and x 6.8 respectively.
F,G. Monoclimacis linnarssoni (Tullberg), sakmaricus-laqueus Zone
F. Peel River, collection at 642.5 m, ROM 38788; x 3.4.
G. Mount Sekwi, collection at 384 m, ROM 38789; x 3.4.
HI. Monograptus parapriodon Bouéek, sakmaricus-laqueus Zone
H. Rock River, main branch, collection 3F, ROM 38790; x 6.8.
1. Peel River, collection at 635.5 m, ROM 38791; x 3.4.
J.K,L. Monograptus pseudobecki Boucek and P¥ibyl, Peel River
JL. Collection at 523 m, turriculatus Zone, ROM 38792 and 38793; both x 6.8.
K. Collection at 519.4 m, sedgwicki Zone?, ROM 38794; x 3.4.
M. Monograptus planus obtusus Schauer, Peel River, collection at 531.9 m, turriculatus
Zone, ROM 38795; x 3.4.
N,P,R. Monograptus sidjachenkoi (Obut and Sobolevskaya), Peel River, convolutus Zone
N,P. Collection at 507.8 m, ROM 38796 and 38797; both x 6.8.
R. Collection at 512.8 m, ROM 38798; x 3.4.
0.Q. Monograptus cf. tenuissmus (Obut and Sobolevskaya), Peel River, collection at
519.4 m, sedgwicki Zone?, ROM 38799 and 38800; both x 3.4.
S,T. Monograptus proteus (Barrande), Rock River, collection at 287 m, turriculatus Zone,
ROM 38801 and 38802; both x 4.
34
Discussion
R. geinitzianus angustidens is very much more common and ubiquitous in the
available collections than is the larger, more robust R. geinitzianus geinitzianus from
which it is distinguished principally by being considerably narrower and in possessing
a finer reticulum. Uncompressed specimens from the Cape Phillips Formation,
Cornwallis Island, show that the virgula is embedded in one side of the central,
boxlike clathria.
Pores, such as those observed by Bjerreskov (1975) in one of her specimens, have
not been recognized in anv of the compressed or uncompressed specimens.
Genus Stomatograptus Tullberg, 1883
Type Species
Retiolites grandis Suess, 1851, from the Lower Silurian of Czechoslovakia; original
designation.
Stomatograptus grandis grandis (Suess, 1851)
Fig. 16A-C
Retiolites grandis Suess, 1851: 15.
Retiolites (Stomatograptus) grandis grandis Boucek and Munch, 1943: 49.
Stomatograptus grandis grandis, Bjerreskov, 1975: 39.
Occurrence
Spiralis and sakmaricus-laqueus zones. Collected from Rock River collections 4F,
SF, 6F, and 8F; and Tetlit Creek, at 185 and 187 m.
Material
Relatively rare with preservation ranging from fair to very good. Illustrated
specimens are ROM 38878 to 38879.
Description
The rhabdosome is greater than 60 mm in length and attains a width of 5.5 to
7.0 mm, the most rapid widening occurring in the proximal 3 cm.
36
The meshwork of the reticulum has three to three and one-half meshes per mm. A
median row of pores may or may not be present throughout the length of the
rhabdosome; the pores are oval in outline and are spaced three to four per 5 mm.
The thecae are inclined about 50 degrees to the virgula distally and overlap about
seven-eighths their length. The interthecal septa are straight, and the external walls of
the thecae are sclerotized and convex in profile. The thecae number 12 to 14 in
10 mm proximally and 8 to 10 in 10 mm distally.
Discussion
S. grandis grandis is readily distinguishable from S. grandis imperfectus by being
narrower, by more consistently possessing the median row of pores and, most
characteristically, by the convex profile of the outer walls of the thecae.
Stomatograptus grandis imperfectus (Boucek and Munch, 1943)
Fig. 16D, F, G
Retiolites (Stomatograptus) grandis imperfectus Boucek and Munch, 1943: 51.
Stomatograptus grandis imperfectus, Munch, 1952: 80.
Occurrence
Spiralis and sakmaricus-laqueus zones. From Tetlit Creek, at 215 and 219 m; Peel
River, at 630.9 m; Rock River, collection 6F; Clearwater Creek, at 88.4 m; and
Beaver River, a spot collection.
Material
Generally only one or two moderately to well-preserved specimens in each collection.
Illustrated specimens are ROM 38880 to 38882.
Description
The rhabdosome is long, the longest observed specimen being 80 mm. Width
increases rapidly from about 1 mm proximally to about 5 mm by the level of theca 20
and more gradually thereafter to attain a maximum width of 6 to 7.5 mm (average:
6.5 mm).
The network of the reticulum is quadrate to polygonal, and two to three network
meshes occur per 1 mm. Some specimens possess a discontinuous row of median
pores with thickened rims, whereas other specimens in the same collection are devoid
of pores.
The thecae are inclined about 60 degrees to the virgula in the distal region and
overlap about three-fourths their lengths. The thecal apertures are concave and the
Sf
proximodistal portion of each theca is drawn out into a liplike structure. Some
compressed specimens clearly show that the lip is really a thin, but completely
sclerotized, shelf which forms the base of the distal part of each theca. Interthecal
septa are robust and straight. Theca number 10 to 14 in 10 mm proximally and eight
to nine in 10 mm distally.
Discussion
The presence of median pores is generally considered diagnostic of the genus
Stomatograptus (see for example Bulman, 1970: V130). Boucek and Minch (1943)
found pores in only some species of Stomatograptus, whereas Bjerreskov (1975)
reports the presence of median pores in one specimen identified as Retiolites
geinitzianus angustidens. It therefore appears that the absence of median pores does
not exclude a species from the genus Stomatograptus. A more diagnostic and
consistent feature of Stomatograptus appears to be the possession of solid interthecal
septa in the distal parts of the thecae. Boucek and Miinch (1943) admit that their
Retiolites robustus is very similar to S. grandis imperfectus, but assign it to Retiolites
because the reticulum is not fused to the clathria, a distinction which seems
exceedingly subtle or inapplicable at best, when working with flattened specimens.
All specimens studied that possess a solid interthecal septum are assigned to the genus
Stomatograptus.
Yukon specimens attain a slightly greater width than is typical of S. grandis
imperfectus which approaches that of §. grandis maior Boucek. However, the
presence of the liplike development is characteristic of S. grandis imperfectus and
quite unlike the convex curvature of the outer walls of the thecae of §. grandis maior.
Fig. 9 A-c. Monograptus cf. sartorius Tornquist, Rock River, collection at 306 m, spiralis Zone?
ROM 38803, 38804, and 38805; all x 8.
D,E. Monograptus sedgwicki (Portlock), Peel River
D. Collection at 516.3 m, turriculatus Zone, ROM 38806; x 3.4.
E. Collection at 513.6 m, sedgwicki Zone, ROM 38807; x 3.4.
F,G. Monograptus rickardsi minor Hutt, Rock River, collection at 287 m, turriculatus
Zone, ROM 38808 and 38809; both x 4.
H-J. Monograptus runcinatus richardsonensis subsp. nov., turriculatus Zone
H. Blackstone River, collection at 94.8 m, ROM 38810; x 6.8.
IJ. Rock River, collection at 287 m, ROM 38811 and 38812; both x 8.
K. Monograptus speciosus Tullberg, Tetlit Creek, collection at 217 m, sakmaricus-
laqueus Zone, ROM 38813; x 8.
L,M,Q. Monograptus triangulatus fimbriatus (Nicholson), Peel River
L,Q. Collection at 488 m, magnus Zone?, ROM 38814 and 38815; x 6.8.
M. Collection at 482.5 m, triangulatus Zone, ROM 38816; x 6.8.
N. Monograptus turriculatus (Barrande), Peel River, collection at 531.9 m, turriculatus
Zone, ROM 38817; x 3.4.
O Monograptus cf. triangulatus separatus Sudbury, Peel River, collection at 480.4 m,
triangulatus Zone, ROM 38818; x 3.4.
P Monograptus spiralis (Geinitz), Peel River, collection at 611.4 m, spiralis Zone, ROM
38819; x 3.4.
Stomatograptus sp.
Fig isi
Occurrence
Sakmaricus-laqueus Zone, Tetlit Creek, at 217 m.
Material
Two incomplete, moderately well-preserved specimens on black shale. The
illustrated specimen is ROM 38877.
Description
Only the distal portion of the rhabdosome is preserved, but the length clearly exceeds
35 mm. Distal width exceeds 4.5 mm. The meshwork of the reticulum is fairly fine,
and the meshes are more or less quadrate and about five in 1 mm. A row of large
median pores is present throughout the length of the rhabdosome. The pores are
ovate, 1.1 to 1.3 mm long and 0.5 to 0.6 mm wide and spaced at the rate of three in
5 mm.
The thecae are straight, overlap about three-fourths their length and number 10 in
10 mm distally. The thecal apertures are concave, and form acute angles with the
axes of the thecae, but show no sclerotization or thickening of the apertural regions.
Discussion
The two Tetlit Creek specimens are most like Stomatograptus shigianensis Mu et al.
(1974) and S. sinensis Wang, although their width suggests a greater affinity with the
former species.
The row of very large median pores is distinctive of the species and, in this respect,
it is quite different from all well-known species. The lack of sufficient material
however, prevents a more detailed discussion or description.
Genus Pseudoplegmatograptus Pribyl, 1948
Type Species
Retiolites perlatus var. obesus Lapworth, 1877, from the Llandovery of Ireland;
original designation.
40
Pseudoplegmatograptus giganteus (Boucek and Munch, 1943)
Fig< 17¢,D
Plegmatograptus giganteus Boucek and Munch, 1943: 17.
Plegmatograptus giganteus, Munch, 1952: 75.
Occurrence
Spiralis Zone, Delorme Range, at 976.9 m.
Material
Two incomplete, moderately well-preserved specimens on grey shale. Illustrated
specimens are ROM 38885 to 38886.
Description
The rhabdosome was evidently much longer than the 55 mm fragment. The width is
10.5 mm inclusive of lacinia, 8.5 mm exclusive of the lacinia. The reticulum is very
coarse, and each mesh is more or less hexagonal and attains a width of 1.5 to
2.0 mm. The rhabdosome is composed of four to five rows of meshes. A thin virgula
is present throughout the length of the rhabdosome.
The thecae are marked by long and slightly proximally curved spines of the lacinia
which emerge from the corner of the outer row of the meshes. Thecae number seven
and a half to eight in 10 mm distally. The ends of the spines of the lacinia are
embedded in an approximately 1 mm wide band of delicate, but dense-textured tissue
(the ‘‘Borste’’ of Boucek and Minch, 1943).
Discussion
The large size, coarse reticulum, and marginal tissue band are distinctive of the
species.
Pseudoplegmatograptus obesus obesus (Lapworth, 1877)
Figs. 16E; 17A, B
Retiolites perlatus var. obesus Lapworth, 1877: 137.
Retiolites (Plegmatograptus) obesus, Elles and Wood, 1908: 342.
Plegmatograptus obesus obesus , Boucek and Minch, 1943: 6.
Retiolites (Pseudoplegmatograptus) obesus, Schauer, 1971: 84.
Pseudoplegmatograptus obesus obesus, Hutt, 1975: 47.
41
Occurrence
Sedgwicki and turriculatus zones, Peel River, at 513.6, 519.4, and 521.8 m; and
Rock River, at 302 m. A single specimen, tentatively identified as this species, was
collected from the convolutus Zone, Peel River, at 507.8 m.
Material
Rare in any collection. Several well-preserved, flattened specimens of this rare
species are present in the collections. The illustrated specimen is ROM 38884.
Description
The rhabdosome is longer than 40 mm and the greatest width attained is 5.5 mm. The
meshwork of the reticulum is distinct, moderately strong, but with a loose
appearance. The meshes are irregular in shape. A lacinia is fairly well developed, is
about 1 mm wide and marks the position of the thecae which number 10 to 12 in
10 mm distally. A median virgula extends throughout the length of the rhabdosome
but a clathria is not seen.
Pseudoplegmatograptus obesus reticulatus (Boucek and Munch, 1943)
Fig. 18B,C
Plegmatograptus obesus reticulatus Boucek and Munch, 1943: 9.
Pseudoplegmatograptus obesus reticulatus, Hutt, 1975: 48.
Occurrence
Turriculatus Zone, Peel River, at 518.8 and 548.9 m.
Fig. 10 A,B. Monograptus tullbergi spiraloides (Pribyl) Rock River, collection 5F, spiralis Zone,
ROM 38820 and 38821; both x 3.4.
C.J. Rastrites approximatus Perner, Peel River, triangulatus Zone
C,J. Collection at 480.4 m, ROM 38822 and 38823; both x 3.4.
1. Collection at 480 m, ROM 38824; x 3.4.
D,K,L. Monograptus revolutus Kurck, Peel River
D. Collection at 488 m, magnus Zone?, ROM 38825; x 3.4.
K. Collection at 471.5 m, gregarius Zone, ROM 38826; x 6.8.
L. Collection at 482.5 m, triangulatus Zone, ROM 38827; x 6.
E. Rastrites cf. distans Lapworth, Peel River, collection at 513.6 m, sedgwicki Zone,
ROM 38828; x 3.4.
F-H. Rastrites longispinus Perner, Peel River
F,G. Collection at 477 m, triangulatus Zone, ROM 38829 and 38830; both x 3.4.
H. Collection at 507.8 m, convolutus Zone, ROM 38831; X 3.4.
42
Material
Two incomplete moderately well-preserved specimens on black shale. Illustrated
specimens are ROM 38891 to 38892.
Description
The rhabdosome is longer than 10 mm and the greatest width is 3.5 mm. The
reticulum is very well developed and is dense, and the meshes are polygonal in
outline and number about 3 in 1 mm. The thecae number 16 to 12 in 10 mm and are
distinct, owing to a moderately well-developed lacinia.
Discussion
This subspecies differs from P. obesus obesus in possessing a dense meshwork and
more closely spaced thecae. The study specimens possess more closely spaced thecae
than the material described by Boucek and Munch (1943).
Pseudoplegmatograptus obscurus (Boucek and Munch, 1943)
Fig. 18D
Plegmatograptus obscurus Boucek and Munch, 1943: 15.
Plegmatograptus obscurus , Munch, 1952: 74.
Occurrence
Spiralis Zone, Rock River, at 326 m, and Tetlit Creek, at 182 m.
Material
Three slightly distorted and incomplete specimens, two moderately well preserved.
The illustrated specimen is ROM 38893.
Description
The rhabdosome is clearly much longer than the fragments available and the
maximum width attains 8 to 9 mm distally. The reticulum is well developed and thin
walled, and forms somewhat irregular to very regular hexagonal meshes which are
about 1 mm in width. The meshes of the outer rows are distinctly hexagonal in
outline and the margin of the rhabdosome is markedly zigzag, marking the position
of the thecae which number 8 to 9 in 10 mm. A virgula is present throughout the
length of the preserved portions of the rhabdosome.
44
Discussion
The Yukon specimens of the species are identical in all respects to the material of
Boucéek and Munch (1943). This species differs from P. giganteus in being narrower
and in lacking the lacinia with the dense marginal band.
Suborder Monograptina Lapworth, 1880
Family Monograptidae Lapworth, 1873
Genus Lagarograptus Obut and Sobolevskaya, 1968
Type Species
Lagarograptus inexpeditus Obut and Sobolevskaya, 1968, from the triangulatus
Zone of the Norilsk borehole, Siberia; original designation.
Lagarograptus cf. acinaces (Tornquist, 1899)
Pisses 4G, By PSA. C.D
cf. Monograptus acinaces Tornquist, 1899: 5.
Occurrence
Acinaces Zone of Peel River, at 460.6 and 461.5 m, and Rock River, at 243 m, and
from the gregarius Zone, Rock River, at 244, 245, 249, and 254 m.
Material
Relatively few, incomplete, flattened specimens from each of the collections.
Illustrated specimens are ROM 38718 to 38720 and 38896.
Description
The rhabdosome is moderately to strongly dorsally curved proximally, gently curved
distally. The sicula is rarely seen, but appears to be at least 3 mm long. The proximal
thecae overlap about one-third, whereas distal thecae overlap one-half to two-thirds.
They are inclined 15 to 20 degrees to the axis of the stipe, are slightly geniculated in
the proximal region and are slightly flaring in the apertural regions. Thecae number 9
to 10 in 10 mm proximally and 8 to 10 in 10 mm distally. The rhabdosome width
ranges from 0.25 to 0.35 mm to 1.1 to 1.3 mm distally.
45
Discussion
The recognition of this species is difficult because very few specimens have the
sicular region preserved and because the sicula is relatively poorly preserved. The
available specimens differ from the typical L. acinaces in that it apparently possesses
a shorter first theca. They also appear to differ in possessing more closely spaced
proximal thecae, although Churkin and Carter (1970) indicate a constant number of
thecae throughout the rhabdosomal length of specimens from southeastern Alaska.
The Canadian specimens are similar to L. acinaces in overall rhabdosome’ shape,
thecal shape, and thecal overlap.
Lagarograptus inexpeditus Obut and Sobolevskaya, 1968
Fig. 4C, M, N; 19E
Lagarograptus inexpeditus Obut and Sobolevskaya, 1968: 91.
Occurrence
Triangulatus Zone, Peel River, at 481.9, 482.5, and 489.2 m.
Material
Numerous poorly preserved fragments; some moderately well-preserved specimens
on black shale. Illustrated specimens are ROM 38726, 38727, and 38898.
Description
The rhabdosome is _ parallel-sided, and generally uniformly dorsally curved
Fig. 11 A,B. Rastrites maximus Carruthers, Peel River, collection at 521.8 m, turriculatus Zone,
ROM 38832 and 38833; both x 3.4.
C.D. Rastrites orbitus Churkin and Carter, Peel River, convolutus Zone
c. Collection at 512.8 m, ROM 38834; x 3.4.
D. Collection at 508.4 m, ROM 38835; x 6.8.
E. Rastrites cf. orbitus Churkin and Carter, Peel River, collection at 508.4 m, convolutus
Zone, ROM 38836; x 3.4.
F,H. Rastrites cf. perfectus Pfibyl, Peel River, collection at 519.4 m, sedgwicki Zone?,
ROM 38837 and 38838; both x 3.4.
GJM. Rastrites phleoides Tornquist, Peel River, convolutus Zone
G,M. Collection at 507.8 m, ROM 38839 and 38840, both x 3.4.
J. Collection at 491.4 m, ROM 38841; x 3.4 (three fragments).
I,.K,L. Rastrites rostratus sp. nov. Peel River, collection at 515.1 m, sedgwicki Zone, ROM
38842, 38843, and 38844; all x 6.8.
47
throughout, width ranges from 0.4 mm proximally to a maximum of 0.5 mm distally.
The sicula is visible on only one specimen and is 2.0 mm long.
The thecae are strongly geniculated and possess parallel-sided (?) processes which
project about 0.4 mm in a ventroproximal direction from the distal end of the thecae.
The thecae number seven to eight in 10 mm throughout.
Discussion
L. inexpeditus is very similar to L. tenuis (Portlock), and is distinguished by being
narrower, possessing more numerous proximal thecae, and, especially, by the
possession of apparently parallel-sided, rather than triangular (cf. Hutt, 1975: 71)
thecal processes. The Yukon material appears to differ from Obut and
Sobolevskaya’s type in possessing a shorter sicula; however, as noted, the sicula was
seen in only a single specimen.
Genus Afavograptus Rickards, 1974
Type Species
Monograptus atavus Jones, 1909, from the Llandovery beds of Wales; original
designation.
Atavograptus cf. gracilis Hutt, 1975
Pigs: 4A 08): Lona
cf. Atavograptus gracilis Hutt, 1975: 63.
Occurrence
Atavus Zone, Blackstone River, at 61.9 m; from the acinaces Zone, Peel River, at
461.5 m, and Pat Lake, collection 3F; and from the gregarius Zone of Rock River,
249 m.
Material
One to several poorly to moderately well-preserved specimens on black shale from
each locality. Illustrated specimens are ROM 38710 to 38712 and 38899.
Description
The rhabdosome is curved gently dorsally, is long and delicate, and increases in
width very gradually from 0.3 to 0.35 mm across theca | to a maximum distal width
48
of 0.5 mm. The longest specimens exceed 50 mm in length. The sicula is a narrow
cone, and although difficult to measure with confidence, appears to be about 1.8 mm
long.
The theca are simple tubes, 2.0 to 2.1 mm long, weakly geniculated, overlapping
about one-half, and are parallel-sided, or are inclined at a very low angle to the axis of
the stipe; they number 10 to 8 in 10 mm.
Discussion
The long slender rhabdosome and simple, weakly geniculated thecae are distinctive
of A. gracilis. Poor preservation of the Yukon specimens, however, prevents a more
accurate assessment of the thecal and sicular characteristics.
Atavograptus strachani (Hutt and Rickards, 1970)
Figs. 41, J, K, R, S; 19B, F, G
Monograptus incommodus, Elles and Wood, 1910: 406.
Monograptus strachani Hutt and Rickards, 1970: 75.
Monograptus strachani, Rickards, 1970: 65.
Atavograptus strachani, Hutt, 1975: 64.
Occurrence
Rare in the atavus Zone, most common in the adcinaces Zone, and uncommon in the
gregarius Zone. From Peel River, at 460, 461.5, and 463 m; Tetlit Creek, at 133 m;
Blackstone River, at 62.5 m; and Rock River, at 241 m. Tentatively identified from
Peel River, at 470.3 m, and from Blackstone River, 62.2 m.
Material
Several to about a dozen poorly to moderately well-preserved specimens from each
collection on black shale. Illustrated specimens are ROM 38721 to 38725 and 38897.
Description
The rhabdosome is curved gently dorsally throughout its length, although the
proximal region may be more strongly curved. Rhabdosomal width ranges from 0.3
to 0.35 mm across theca 1 to an average of 0.8 to 0.9 mm distally, although
occasionally specimens attain a maximum of 1.0 to 1.2 mm. The sicula is long and
slender, attaining a length of 4 to 4.5 mm, although some appear to be as short as
3 mm in length.
The thecae are simple tubes, slightly geniculated and inclined at a very low angle;
they overlap one-half to two-thirds their length and number seven to eight in 10 mm.
The thecal aperture typically forms an acute angle with the axis of the theca.
49
Discussion
The relatively long sicula, slightly geniculated thecae inclined at very low angles, and
the short proximal thecae are distinctive of the species. The last characteristic serves
to distinguish it from the otherwise similar L. acinaces.
Genus Coronograptus Obut and Sobolevskaya, 1968
Type Species
Monograptus gregarius Lapworth, 1876, from the Llandovery of Scotland; original
designation.
Coronograptus cf. cyphus (Lapworth, 1876)
Fig. 4F
cf. Monograptus cyphus Lapworth, 1876: 352.
Occurrence
Gregarius Zone, Rock River, at 255 m.
Material
Two poorly preserved and incomplete specimens compressed on black shale. The
illustrated specimen is ROM 38717.
Fig. 12 A-c,H. Petalograptus altissimus Elles and Wood
A,B. Blackstone River, collection at 91.4 m, turriculatus Zone, ROM 38845 and
38846; both x 3.5.
c. Peel River, collection at 531.9 m, turriculatus Zone, ROM 38847; x 4.0.
H. Blackstone River, collection at 72.2 m, sedgwicki Zone, ROM 38850; x 2.4.
D,E. Petalograptus folium (Hisinger), Peel River, convolutus Zone
D. Collection at 498.7 m, ROM 38848; x 2.9.
E. Collection at 496.2 m, ROM 38849; x 2.7.
FI-L. Petalograptus intermedius (Boucek and Priby])
F. Peel River, collection at 487.4 m, triangulatus Zone, ROM 38851; x 4.6.
Jk. Blackstone River, collection at 72.2 m, sedgwicki Zone, ROM 38852 and
388535 2205 2.8)
1. Blackstone River, collection at 77.2 m, sedgwicki Zone, ROM 38678; X 3.8.
L. Blackstone River, collection at 70.4 m, convolutus Zone, ROM 38855; xX 3.4.
G. Petalograptus cf. hispanicus Haberfelner, Peel River, collection at 544.4 m,
turriculatus Zone, ROM 38856; x 4.0.
50
saree. Spetsce':.
let Sei
*
if
Discussion
The availability of only two, poorly preserved specimens prevents a detailed
description; nevertheless, the importance of C. cyphus as a zonal indicator warrants
documentation. Main characteristics of the species include a delicate proximal
portion, a rapid distal widening of the rhabdosome, slight flexure of the distal thecae,
and the strong overlap of the distal thecae. The thecae in the study specimens number
nine in 10 mm proximally and maximum observed width is 1.2 mm.
Coronograptus gregarius gregarius (Lapworth, 1876)
Figs. 4D,E,0,Q; 20B-D
Monograptus gregarius Lapworth, 1876: 317.
Monograptus gregarius, Elles and Wood, 1911: 365.
Coronograptus gregarius gregarius, Obut and Sobolevskaya, 1968: 92.
?Monograptus gregarius, Churkin and Carter, 1970: 39.
Monograptus gregarius, Bjerreskov, 1975: 46.
Coronograptus gregarius gregarius, Hutt, 1975: 64.
Pristiograptus gregarius, Chen and Lin, 1978: 53.
Occurrence
Gregarius Zone, Peel River, at 465.1 and 472.7 m, and Rock River, 254 m;
triangulatus Zone, Peel River, at 477, 487.4, and 489.2 m; and magnus? Zone, Peel
River, at 485.9 and possibly at 488 m.
Material
Dozens of specimens, all incomplete, but many including proximal ends. Illustrated
specimens are ROM 38713 to 38716 and 38900.
Description
The rhabdosome is strongly dorsally curved, up to the fifth to seventh thecae, and
gently curved thereafter. The sicula ranges from 4 to 6 mm in length and its apex
attains the level of the tip of theca 3 or 4. The thecae are weakly sigmoidal, flaring
towards the aperture and numbering eight to ten in 10 mm proximally and eight to
nine in 10 mm distally. Rhabdosomal width ranges from 0.5 to 0.55 mm across theca
1 to 0.7 to 0.8 mm distally. A single 5-cm-long fragment attains a distal width of
1.4 mm.
Discussion
C. gregarius gregarius is characterized by its long sicula, flaring thecal apertures
52
and, to some extent, by its thecal spacing. Among the Yukon collections, sicula
lengths do not attain those noted by Hutt (1975) and Bjerreskov (1975), even though
the specimens available range through three zones. On the other hand, the sicula
length of the study material is considerably greater than that of the Alaskan specimens
of Churkin and Carter (1970).
C. gregarius gregarius is distinguished from C. gregarius arcuatus of this study
primarily by its greater width and more robust rhabdosome.
Coronograptus gregarius arcuatus Obut and Sobolevskaya, 1968
Figs: SC) Dar: 20k. G, He!
Coronograptus gregarius arcuatus Obut and Sobolevskaya, 1968: 94.
?Pristiograptus tenellus, Chen and Lin, 1978: 56.
Occurrence
Acinaces Zone, Pat Lake, collection 3F; gregarius Zone, Peel River, at 470.3, 472.7,
474, and 475.5 m; Tetlit Creek, at 136 m; and Rock River, at 244 m; and gregarius
or triangulatus Zone, Peel River, at 475.5 m.
Material
Dozens of specimens, preserved as impressions on black shale. Illustrated specimens
are ROM 38731 to 38733 and 38901 to 38904.
Discussion
C. gregarius arcuatus is distinguised from C. gregarius gregarius by its weaker
dorsal curvature and lesser width. The thecal spacing of 10 to 8 in 10 mm in the
specimens available is, however, unlike that of the types of Obut and Sobolevskaya
(1968). The sicula of the study material ranges from 3.5 to 5.0 mm in length and its
apex attains the level of the tip of theca 3. Rhabdosomal width is 0.4 to 0.45 mm
initially and increases gradually to a maximum of 0.5 to0.55 mm distally. Specimens
assigned to the new species Pristiograptus tenellus by Chen and Lin (1978) may
belong to C. gregarius arcuatus.
Coronograptus hipposideros (Toghill, 1968)
Figs. 5A, B, E; 20E, I
Monograptus hipposideros Toghill, 1968: 384.
53
be Sea fl A sass eo ew SS AP
*
a
54
Occurrence
Gregarius Zone, Peel River, at 468.2, 469.4, and 471.5 m; and Rock River, at
235 mM:
Material
A few mostly incomplete, moderately well-preserved specimens from each
collection. Illustrated specimens are ROM 38728 to 38730.
Description
The rhabdosome is horseshoe-shaped in curvature, and may be most strongly flexed
about the level of theca 3 or 4. Rhabdosomal width ranges from 0.5 to 0.6 mm across
theca 1, to a maximum distal width of 0.7 to 0.8 mm. The sicula is generally about
3 mm or slightly less in length and its apex attains the level of the end of theca 2 or 3.
The thecae are sigmoidal in profile and flare towards the apertures, as inC. gregarius
(sensu stricto), and overlap one-third proximally and one-half distally.
Discussion
Toghill (1968), noted that the most distinctive character of this species is its strong
dorsal curvature. Curvature in some specimens studied is almost 360 degrees.
Genus Pribylograptus Obut and Sobolevskaya, 1966
Type Species
Monograptus incommodus Tornquist, 1899, from the Llandovery of Sweden; original
designation.
Fig. 13 a,c,H. Petalograptus ovatoelongatus (Kurck), Peel River, turriculatus Zone
A. Collection at 523 m, ROM 38687; xX 2.6.
c. Collection at 521.8 m, ROM 38686; x 2.5.
H. Collection at 516.3 m, ROM 38688; x 3.0.
B,D,G. Petalograptus elongatus (Boucek and Pribyl), turriculatus Zone
B. Rock River, collection at 287 m, ROM 38856; x 5.4.
D. Blackstone River, collection at 80.2 m, ROM 38857; xX 2.8.
G. Blackstone River, collection at 88.7 m, ROM 38858; xX 2.8.
E Petalograptus cf. palmeus clavatus (Bouéek and Pribyl), Peel River, collection at
518.8 m, turriculatus Zone, ROM 38859; x 3.1.
Fl. Petalograptus cf. palmeus palmeus (Barrande), Peel River, turriculatus Zone
F. Collection at 518.8 m, ROM 38860; x 3.0.
1. Collection at 523 m, ROM 38861; x 4.2.
N
Nn
Pribylograptus angustus (Rickards, 1970)
Figs. 5Q; 20A
Monograptus angustus Rickards, 1970: 89.
Occurrence
A single specimen from the magnus? Zone of Peel River, at 488 m, and another
specimen tentatively identified as this species from the gregarius Zone, 465.1 m. The
illustrated specimen is ROM 38746.
Description
The specimen is incomplete and threadlike, 30 mm long, and 0.25 mm wide
throughout its length. The proximal end is missing. The thecae overlap only slightly,
are inclined at a very low angle to the axis of the stipe, and number 6 in 10 mm. The
ventral side of the thecae are more or less straight throughout, but the thecal apertures
may be slightly flaring. The nature of the aperture is difficult to discern, but appears
to be introverted.
Discussion
The single specimen has the same width and thecal spacing as does Rickard’s (1970)
type. The possession of probably introverted thecal apertures provides additional
evidence for this specific assignment.
Pribylograptus cf. argutus (Lapworth, 1876)
Fig. 18F
cf. Monograptus argutus Lapworth, 1876: 318.
Occurrence
Convolutus Zone, Blackstone River, at 70.4 m.
Material
Several incomplete, only moderately well preserved, flattened specimens on black
shales. The illustrated specimen is ROM 38895.
56
Description
The rhabdosome is broadly and arcuately curved in a dorsal direction. No proximal
ends are preserved, but the width is about 0.3 mm in the most proximal section
preserved; it increases gradually to a maximum distal width of 0.95 mm. The thecae
are distinctly sigmoidal in profile throughout the length of the rhabdosome and appear
to have introverted thecal apertures. They overlap one-third proximally and
two-thirds distally, and number 10 to 9 in 10 mm.
Discussion
The presence of simple tubelike thecae with introverted apertures, a diagnostic
feature of the species, is difficult to establish because of poor preservation. The
Yukon specimens are very similar in all other characteristics to the descriptions given
by Elles and Wood (1911), Rickards (1970), and Hutt (1975).
Pribylograptus sp.
Fig. 18E
Occurrence
Gregarius Zone, Peel River, at 470.3 m.
Material
A single, moderately well-preserved, long, incomplete specimen on black shale. The
illustrated specimen is ROM 38894.
Discussion
This species is characterized by the possession of a long, narrow rhabdosome, not
exceeding 0.55 mm in width, a thecal spacing of five to six in 10 mm, and long, very
narrow, weakly inclined thecae which overlap about one-half their length. The
apertural regions are distinctly retroverted and pinched, and the apertures are directed
laterally in a manner similar to that of P. incommodus (Tornquist). This species
differs however, from P. incommodus, P. argutus (Lapworth), and P. argutus
sequens (Rickards), in possessing much more widely spaced thecae. It is most similar
in overall dimensions to Pristiograptus sp. 2 of Hutt (1975: 52), but differs in
possessing retroverted thecal apertures.
57
Genus Pristiograptus Jaeckel, 1889
Type Species
Pristiograptus frequens Jaeckel, 1889, from the Silurian of Germany; original
designation.
Pristiograptus nudus (Lapworth, 1880)
Figs. 5L, M, P; 21D
Monograptus Hisingeri Carruthers var. nudus Lapworth 1880: 156.
Monograptus nudus, Tornquist, 1899: 8.
Monograptus nudus, Elles and Wood, 1911: 375.
Pristiograptus nudus, Rickards, 1970: 59.
Pristiograptus nudus, Schauer, 1971: 62.
Monograptus nudus, Bjerreskov, 1975: 47.
Pristiograptus nudus, Hutt, 1975: 59.
Occurrence
Convolutus and sedgwicki zones; rarely from the turriculatus Zone. Collected from
Peel River, at 515.1, 516.9, 518.8, and 523 m; Blackstone River, at 70.4 and 72.2 m;
possibly Clearwater Creek, at 65.5 m.
Material
One to several, moderately well-preserved specimens from each locality on black
shale. Illustrated specimens are ROM 38743 to 38745.
Fig. 14 a-c. Cephalograptus cometa cometa (Geinitz), Blackstone River, collection at 70.4 m,
convolutus Zone, ROM 38690, 38862, and 38863; x 3.4, x 3.5, x 3.5.
D. Rhaphidograptus cf. toernquisti (Elles and Wood), Peel River, collection at 485.9 m,
magnus Zone?, ROM 38864; x 5.8.
E Cephalograptus tubulariformis (Nicholson), Blackstone River, collection at 69.2 m,
convolutus Zone, ROM 38695; x 3.6.
F, -K. Dimorphograptus physophora alaskensis Churkin and Carter
F,1. Pat Lake, collection 3F, acinaces Zone, ROM 38865 and 38866; x 4.2, x 3.7.
JK. Rock River, collection at 244 m, gregarius Zone, ROM 38867 and 38868;
KOI aS.
G,H. Cephalograptus cometa extrema Bouéek and Pribyl, Blackstone River, collection at
77.2 m, sedgwicki Zone, ROM 38693 and 38869; both x 3.5.
58
Description
The rhabdosome is straight, except for the sicular region, which is weakly dorsally
curved. The sicula is 1.2 to 1.5 mm long. The rhabdosome width is 0.5 mm across
theca | and increases gradually to a maximum of at least 1.5 mm distally. The thecae
overlap one-third their length proximally and one-half distally, and number 12 to 14
in 10 mm proximally and 10 in 10 mm distally.
Discussion
The Yukon specimens are similar to the typical P. nudus in rhabdosomal shape,
dimensions, thecal nature, and overlap. They differ slightly from typical specimens
of that species in possessing somewhat more closely spaced proximal thecae and a
longer sicula. In the latter parameter, however, they overlap that of Bjerreskov’s
(1975) Danish material.
Pristiograptus regularis (Tornquist, 1899)
Figs; Ho 2 ARC
Monograptus regularis Tornquist, 1899: 7.
Monograptus regularis, Elles and Wood, 1911: 372.
Pristiograptus regularis regularis, Rickards, 1970: 59.
Monograptus regularis, Sherwin, 1974: 157.
Monograptus regularis regularis, Bjerreskov, 1975: 47.
Pristiograptus regularis regularis, Hutt, 1975: 58.
Occurrence
Convolutus to turriculatus zones. Collected from Peel River, at 512.8, 516.9, 519.4,
521.8, and 523 m, and Tetlit Creek, at 144 m. Tentatively from Peel River, at 507.8,
523, and’ 526° m:
Material
A few poorly to moderately well-preserved specimens from each collection on black
shale. Illustrated specimens are ROM 38737 to 38739 and 38905 to 38906.
Description
The rhabdosome is straight throughout its length, except for the proximal | to 2 mm,
which is weakly dorsally curved. The width of the rhabdosome increases gradually
from 0.45 to 0.55 mm across theca 1, to a maximum distal width of 1.2 to 1.3 mm.
The sicula is short, about 1.0 mm long, and its apex attains the level of the aperture of
theca 1.
60
The thecae are tubelike, straight, inclined 20 to 30 degrees to the axis of the stipe,
overlap one-fifth to one-third proximally and one-half to two-thirds distally, and the
apertures subtend an angle of 90 degrees to the axis of the thecae. The thecae number
12 to 14 in 10 mm proximally and 9 to 10 in 10 mm distally.
Discussion
P. regularis differs from P. nudus in its more delicate and slender proximal region,
and from P. variabilis in being much more robust and possessing a greater thecal
overlap.
Pristiograptus cf. variabilis (Perner, 1897)
Figsa ke Ne ©
cf. Monograptus jaculum, Lapworth var. variabilis Perner, 1897: 21.
Occurrence
Turriculatus Zone, Peel River, at 523 m; tentatively from Tetlit Creek, at 142 m.
Material
Six moderately well-preserved specimens from Peel River, and a single poorly
preserved specimen from Tetlit Creek. Illustrated specimens are ROM 38740 to
38742.
Description
The rhabdosome is straight throughout its length except for a weak dorsal curvature of
the sicular region. The rhabdosome increases gradually in width from 0.4 mm across
theca 1, to a maximum distal width of about 1.0 mm. The sicula is relatively robust
and is 1.0 to 1.2 mm long.
The thecae are simple, straight tubes, overlapping about one-fifth proximally and
one-half distally, inclined about 15 degrees to the axis of the stipe and number 10 to 9
in 10 mm.
Discussion
The characteristics of the study material agree well with the description of this species
by Elles and Wood (1911). The Yukon occurrence of the species is one zone lower
than the British occurrence of the species, but is the same as that in Germany
(Schauer, 1971) and Czechoslovakia (Munch, 1952).
61
Genus Monoclimacis Frech, 1897
Type Species
Graptolithus vomerinus Nicholson, 1872, from the Llandovery of northern England;
original designation.
Monoclimacis linnarssoni (Tullberg, 1883)
Fig. 8F,G
Monograptus linnarssoni Tullberg, 1883: 20.
Monograptus linnarssoni, Waterlot, 1945: 77.
Monograptus linnarssoni, Bjerreskov, 1975: 54.
Occurrence
Sakmaricus-laqueus Zone, Peel River, at 638.6 and 642.5 m; and Mount Sekwi, at
384 m. Tentatively identified from Peel River, 640.1 m.
Material
Two to three incomplete specimens occur in each collection; only three moderately
well-preserved specimens are available. All are flattened on grey or black shale.
Illustrated specimens are ROM 38788 to 38789.
Description
The rhabdosome is long, delicate, and greater than 50 mm, and more or less straight
Fig. 15 A,B. Dimorphograptus confertus swanstoni Lapworth
A. Peel River, collection at 460 m, acinaces Zone, ROM 38870; x 2.7.
B. Blackstone River, collection at 62.2 m, atavus Zone? ROM 38698; x 2.3.
C,H. Retiolites geinitzianus angustidens Elles and Wood, spiralis Zone
Cc. Peel River, collection at 615.7 m, ROM 38871; x 5.8.
H. Rock River, main branch, collection 1F, ROM 38872; x 4.0.
D,E. Dimorphograptus cf. physophora (Nicholson)
D. Blackstone River, collection at 61.9 m, atavus Zone?, ROM 38873; x 2.7.
E. Rock River, collection at 244 m, gregarius Zone, ROM 38874; x 4.6.
F. Retiolites decurtatus Boucek and Miinch, Blackstone River, collection at 66.4 m,
convolutus Zone, ROM 38875; x 3.8.
G. Pseudoplegmatograptus sp., Peel River, collection at 531.9 m, turriculatus Zone,
ROM 38876; x 5.6.
|. Stomatograptus sp., Tetlit Creek, collection at 217 m, sakmaricus-laqueus Zone, ROM
SS87 7x 3.6.
throughout its length. Width increases imperceptibly from 0.3 mm or less proximally
to a maximum of at least 0.75 mm distally. The sicula was not seen.
The thecae are typically monoclimacid, overlap one-quarter their length proximally
and nearly one-half distally; they are strongly sigmoidal and the metathecal portions
while parallel to the stipe axis overall are slightly arched or ‘‘humpbacked’’ in
profile. Generally, the thecal apertures are marked by deep excavations and end
against very weak hoodlike structures. Thecae number seven to eight in 10 mm.
Genus Monograptus Geinitz, 1852 emended
Type Species
Lomatoceras priodon Bronn, 1835, from the Silurian of Germany; subsequent
designation Bassler, 1915.
Monograptus cf. argenteus (Nicholson, 1869)
Figs 5S. |
cf. Graptolites argenteus Nicholson, 1869: 239.
Occurrence
Argenteus Zone, Peel River, at 491.4 m.
Material
A single incomplete specimen, that is of only fair preservation. The illustrated
specimen is ROM 38747.
Description
The proximal region of the rhabdosome is moderately strongly curved dorsally and
the distal portion is straight. The proximal thecae are inclined about 30 degrees and
overlap about one-third proximally and two-thirds distally. The metathecal portion,
which involves about one third of the thecal length, is strongly hooked and its
aperture faces in a proximodorsal direction. The thecae become less strongly hooked
distally and distal thecae are essentially simple tubes with weakly developed lappets
(?). Maximum width of the stipe is 2.0 mm and the thecae number seven in 10 mm.
Discussion
Scarcity of specimens permits only a tentative identification. The rhabdosome shape
64
of the Yukon specimen is typical of M. argenteus, as is the nature of the biform
thecae (see Hutt, 1975). The single specimen differs from the typical form, however,
in that the proximal thecae are more strongly hooked and the thecae are more widely
spaced.
Monograptus circularis Elles and Wood, 1913
Fie. 2 11
Monograptus circularis Elles and Wood, 1913: 479.
Spirograptus circularis, Pribyl, 1944: 205.
Monograptus circularis, Waterlot, 1945: 86.
Occurrence
Sedgwicki Zone, Peel River, at 513.6 m.
Material
Seven incomplete, moderately well-preserved specimens on black shale. The
illustrated specimen is ROM 38910.
Description
The rhabdosome is planispirally or weakly helically coiled and the greatest
rhabdosomal width observed is 8 mm. The stipe width increases gradually from
0.5 mm proximally, to a maximum distal width of 1.2 mm. The sicula is delicate,
about 1 mm long, and its apex attains the level of the tip of theca 1. The theca are
distinctly triangular in outline, overlap negligibly proximaliy and about one-third
distally, and are weakly hooked only at their distal extremities. Thecae number eight
in 10 mm.
Monograptus clingani (Carruthers, 1867)
Figs: SU, V; 215, K
Graptolithus Clingani Carruthers, 1867: 369.
Monograptus Clingani, Elles and Wood, 1913: 463.
Monograptus clingani, Strachan, 1969: 195.
Monograptus clingani, Hutt, 1975: 82.
Occurrence
Convolutus Zone, Blackstone River, at 70.4 m; Peel River, at 498.7, 502.3, and
65
66
D,F,G.
Stomatograptus grandis grandis (Suess), Rock River, spiralis Zone
A,c. Collection 5F, ROM 38878; x 2.6, x 4.8.
B. Collection 8F, ROM 38879; x 2.9.
Stomatograptus grandis imperfectus (Bouéek and Minch), spiralis Zone
D. Peel River, collection at 630.9 m, ROM 38880; x 1.9.
F,G. Rock River, collection 6F, ROM 38881 and 38882; x 4.2, x 2.2.
Pseudoplegmatograptus obesus obesus (Lapworth), Peel River, collection at 553.8 m,
turriculatus Zone, ROM 38883; x 4.0.
507.8 m; and Delorme Range, at 768.1 m. It is tentatively identified from the
turriculatus Zone, Delorme Range, at 777.2 m.
Material
Several poorly to moderately well-preserved specimens from each collection
preserved on black or grey shale. Illustrated specimens are ROM 38748 to 38749 and
38907.
Description
The rhabdosome is moderately dorsally curved proximally, and progressively less so
distally. The sicular portion and the region of the first one or two thecae may be
abruptly hooked dorsally. The proximal end of the rhabdosome is rather robust and
width increases gradually from about 0.7 mm across theca 1 to a maximum of 1.4 to
1.5 mm distally. The thecae are strongly hooked throughout the length of the
rhabdosome, although the distal thecae may be more strongly hooked and lobate than
the proximal thecae. The proportion of the stipe width occupied by the hooked
portions of the thecae ranges from about one-third proximally to one-half distally.
Thecae number 10 to 8 in 10 mm. The sicula is 1.0 to 1.1 mm long and its apex
reaches the level of the tip of theca 1.
Discussion
Features characteristic of this species are the rather robust proximal end, short sicula,
and particularly the fact that distal thecae are more strongly hooked than proximal
ones. Although the Yukon specimens appear to differ slightly from typical specimens
in possessing more widely spaced thecae, the range observed falls within the
definition of the species, especially as given by Elles and Wood (1913) and probably
also by Strachan (1969) in his redescription of the species.
Monograptus communis Lapworth, 1876
Bigs 5G. 2G. Hi, J. 0
Monograptus convolutus Hisinger, sp. Var. (a) communis Lapworth, 1876: 358.
Monograptus communis, Elles and Wood, 1913: 480 (pars).
Spirograptus communis communis, Pribyl, 1944: 214.
Monograptus communis communis, Sudbury, 1958: 520.
Campograptus communis communis, Obut and Sobolevskaya, 1967: 123.
Monograptus communis communis, Rickards, 1970: 84.
Oktavites communis, Chen and Lin, 1978: 66.
67
Occurrence
Argenteus and convolutus zones, Peel River, at 487.4, 498.7, and 496.2, and
possibly 512.8 m; Blackstone River, at 65.5 and 66.4 m; and possibly Tetlit Creek,
at 142 m.
Material
Abundant in collections from Blackstone and Peel rivers as moderately well-
preserved specimens on black shale. Illustrated specimens are ROM 38734 to 38736
and 38908 to 38909.
Description
The rhabdosome is dorsally curved throughout, more strongly so in the proximal
region. Width increases gradually from 0.6 to 0.7 mm across theca 1, to a maximum
distal width of 1.4 to 1.5 mm. The sicula is 1.1 to 1.2 mm long and its apex reaches
slightly beyond the level of the tip of theca 1.
The thecae are moderately hooked in the proximal region of the rhabdosome,
where they occupy about one-half the width of the stipe, and are strongly hooked to
nearly lobate in the distal region where the metathecal portion occupies more than
half the stipe width. Thecal overlap is negligible proximally, but increases to about
one-third distally.
Discussion
The preservation of the metathecal portion of the distal thecae makes identification
difficult. The illustrations of Elles and Wood (1913) and Sudbury (1958) suggest that
the metathecal portion is only moderately strongly hooked, whereas those of Pribyl
(1944), Obut et al. (1967), and Rickards (1970) clearly indicate strongly hooked
thecae. Elles and Wood (1913) point out that, as a result of torsion of the thecal axis,
the modes of preservation vary considerably. The author has examined specimens of
M. communis at the Sedgwick Museum, Cambridge, which possess moderately to
strongly hooked thecae.
The potential for producing superficially strongly hooked or even lobate thecal
profiles upon compression in M. communis is confirmed by an examination of
uncompressed specimens from the Cape Phillips Formation, Cornwallis Island. The
thecae are triangular is cross-section and, while prothecal portions of the thecae are
parallel to the stipe axis, the metathecal portions show strong torsion. In addition, the
thecal apertures possess weak hoods. Clearly, upon compression, and depending on
the direction of compression, the metathecal portions could come to lie beneath the
slightly more proximal portions of the thecae resulting in a hooked or lobate profile.
The Yukon specimens are similar in every respect to those of Obut et al. (1967).
They are also similar in some respects to M. noyensis of Churkin and Carter (1970),
but differ in being wider and in possessing more widely spaced thecae.
68
This species is similar in many respects to M. clingani from the same zone. It
differs, however, in possessing a much more elongated and delicate proximal portion
and in having proximal thecae that occupy much more of the rhabdosome width.
Monograptus convolutus (Hisinger, 1837)
Rigs: 6B; 2240 F
Prionotus convolutus Hisinger, 1837: 114.
Monograptus convolutus, Tornquist, 1899: 21.
Monograptus convolutus, Elles and Wood, 1913: 467.
Monograptus convolutus, Waterlot, 1945: 88.
Monograptus convolutus, Sudbury, 1958: 511.
Demirastrites convolutus, Obut and Sobolevskaya, 1967: 126.
Monograptus convolutus, Rickards, 1970: 82.
Monograptus convolutus, Bjerreskov, 1975: 81.
Monograptus convolutus, Hutt, 1975: 83.
Occurrence
Convolutus Zone, Peel River, at 496.2, 498.7, and 502.3 m; and Blackstone River,
at 66.4, 69.2, and 70.4 m. Tentatively from Peel River, at 507.8 m.
Material
A few poorly to moderately well-preserved specimens from each collection; two
nearly complete specimens; all compressed on black shale. Illustrated specimens are
ROM 38752 and 38911.
Description
The rhabdosome is planispirally coiled through at least three volutions and attains a
width of at least 20 mm. The sicular portion is not preserved. The stipe width ranges
from about 1.5 mm proximally to a maximum of 2.5 mm in a very short distance and
remains constant thereafter, or decreases slightly. The proximal thecae are isolated
and rastritiform, widen gradually towards their apertural regions, and generally bear
two spines at their distal ends. Distal thecae are more triangular, slightly overlapping,
weakly curved, with the aperture directed in a proximal direction, and generally
appear to bear a single distal spine. Theca number 9 in 10 mm.
Discussion
This species has only rarely been reported previously from North America and was
not included in Ruedemann’s (1947) monumental study of North American
69
graptolites. The form identified by Ruedemann (1947) as M. convolutus coppingeri
Etheridge from the Arctic Islands is probably best re-assigned to M. spiralis.
Monograptus aff. cygneus Tornquist, 1892, sensu Obut and Sobolevskaya, 1967
Figs. 6D, E; 22B, E
Pernerograptus atf. cygneus (Tornquist), Obut and Sobolevskaya, 1967: 10
Occurrence
Argenteus and convolutus zones, Peel River, at 491.4, 495.9, 498.7, 502.3, 506.3,
507.8, 508.4, and 512.8 m; Blackstone River, at 66.4 and 69.2 m.
Material
Few, fairly to moderately well-preserved specimens from each collection. Illustrated
specimens are ROM 38753 to 38754 and 38912.
Description
The rhabdosome is moderately dorsally curved proximally, the curvature decreases
distally, and the distal region is more or less straight. Stipe width ranges from about
0.5 mm across theca 1 to a maximum of 1.1 to 1.2 mm distally. Thecae number nine
to seven in 10 mm.
The thecae are biform, the proximal 8 to 10 being weakly to moderately hooked
and they overlap not more than one-third their length. Distal thecae are inclined at a
low angle, are almost monoclimacid in outline and overlap one-half.
Discussion
The study specimens differ from those of the typical M. cygneus in possessing a more
robust proximal region and almost monoclimacid thecae; in other respects it is very
similar (see for example Elles and Wood, 1913: 387; Miinch, 1952: pl. 25). The
Canadian specimens are clearly very similar to those illustrated by Obut et al. (1967)
and for that reason are tentatively assigned to M. cygneus. The specimens differ from
M. sidjachenkoi (Obut et al., 1967) in possessing a much less curved and more
attenuated proximal region.
Monograptus crispus Lapworth, 1876
Figs. 6M, P
Monograptus crispus Lapworth, 1876: 503.
70
Fig. 17 A,B.
(7)D).
E-G.
Pseudoplegmatograptus obesus obesus (Lapworth), Peel River, collection at 513.6 m,
sedgwicki Zone, ROM 38884; x 2.7, x 5.0.
Pseudoplegmatograptus giganteus (Bouéek and Miinch), Delorme Range, collection
at 976.9 m, spiralis Zone?, ROM 38885 and 38886; x 1.6, x 4.0.
Barrandeograptus aff. pulchellus (Tullberg), Blackstone River, collection at 72.2 m,
sedgwicki Zone, ROM 38887, 38888, and 38889, x 4.2, x 2.7, x 2.4.
71
Fig. 18 A Retiolites perlatus Nicholson, Blackstone River, collection at 91.4 m, turriculatus
We
B,C.
Zone, ROM 38890; x 2.2.
Pseudoplegmatograptus obesus reticulatus, (Bouéek and Minch), Peel River,
turriculatus Zone
B. Collection at 518.8 m, ROM 38891; x 2.9.
c. Collection at 548.9 m, ROM 38892; x 6.4.
Pseudoplegmatograptus obscurus (Bouéek and Minch), Tetlit Creek, collection at
182 m, spiralis Zone, ROM 38893; x 4.1.
Pribylograptus sp., Peel River, collection at 470.3 m, gregarius Zone, ROM 38894;
Pa:
Pribylograptus cf. argutus (Lapworth), Blackstone River, collection at 70.4 m,
convolutus Zone, ROM 38895; x 4.2.
Monograptus crispus, Elles and Wood, 1912: 456.
Monograptus (Streptograptus) crispus, Schauer, 1971: 72.
Monograptus crispus, Bjerreskov, 1975: 74.
Occurrence
Crispus Zone? (correlative in part with the spiralis Zone), Cape Phillips Formation,
Svendsen anticlinorium, Ellesmere Island, Arctic Archipelago.
Material
Five incomplete, moderately well-preserved specimens on a single piece of
light-coloured shale. Illustrated specimens are ROM 38763 to 38764.
Discussion
M. crispus has not been previously reported from the Arctic or Cordilleran regions of
North America. Its discovery in the Arctic Islands is significant because it permits the
tentative recognition of the crispus Zone of late Llandoverian age as defined in
Britain.
The rhabdosome is typically S-shaped, the proximal end being dorsally curved.
The sicula is 1.2 mm long. The width of the stipe increases gradually from 0.3 mm
across theca 1 to an observed maximum of 0.8 to 0.9 mm.
The thecae overlap only slightly, are strongly hooked, occupy one-half to
two-thirds of the stipe width, and number seven in 10 mm proximally and 9 to 10 in
10 mm distally.
Monograptus curvus Manck, 1923
Figs, OA, G: 226 p
Monograptus curvus Manck, 1923: 286.
Spirograptus curvus, Pribyl, 1944: 200.
Spirograptus curvus, Munch, 1952: 115.
Monograptus curvus, Jaeger, 1976: pl. 2
Occurrence
Spiralis Zone, Peel River, at 611.4 m; and Clearwater Creek, at 79.2 m.
Material
Relatively uncommon in collections, and of fair preservation. Illustrated specimens
are ROM 38750 to 38751 and 38913.
73
Description
The rhabdosome is straight or gently ventrally cuved through the distance of the first
seven to nine thecae; the rhabdosome then abruptly undergoes torsion through 180
degrees and is thereafter weakly ventrally curved, although the curvature lessens
distally. The sicula is 1.2 to 1.3 mm long and its apex is at or slightly beyond the
level of the tip of theca 1. The proximal thecae overlap about one-third, whereas
distal thecae overlap two-thirds their length. The proximal thecae are moderately
hooked, the hooked portion occupying about one-half the stipe width; distal thecae
are distinctly triangular in profile, are only gently hooked, and the free portion of the
thecae occupies one-quarter to one-third the stipe width. Thecae number 10 to 7 in
10 mm and the rhabdosome width ranges from 0.6 mm proximally to 1.5 to 1.6 mm
distally.
Discussion
M. curvus has previously been reported only from Germany and Czechoslovakia
(Pribyl, 1944), and from Sardinia (Jaeger, 1976). It is characterized by its curved
rhabdosome with the abrupt torsion and the triangular thecae.
Monograptus decipiens decipiens Tornquist, 1899
Figs: OF/N; 23A,/C,F
Monograptus decipiens Tornquist, 1899: 20.
Monograptus decipiens, Elles and Wood, 1913: 469 (pars).
Demirastrites decipiens decipiens , P¥iby| and Munch, 1942: 12.
Monograptus (Demirastrites) decipiens, Schauer, 1971: 79.
Monograptus decipiens decipiens, Hutt, 1975: 85.
Monograptus decipiens decipiens, Bjerreskov, 1975: 80.
Occurrence
Commonest in the sedgwicki Zone; uncommon in the turriculatus Zone. Found in
Blackstone River, at 76.2 m; and tentatively identified from Peel River, at 526 m; and
Tetlit Creek, at 144 and 168 m.
Material
Abundant at Blackstone River, and relatively uncommon elsewhere, and moderately
well to well-preserved as carbon films on black shale. Illustrated specimens are ROM
38755 to 38756 and 38914 to 38916.
74
Description
The rhabdosome is coiled through at least one volution. The sicula is 0.8 to 0.9 mm
long and its apex reaches the level of theca 1. The first eight to nine thecae are
rastritiform, are inclined about 60 to 70 degrees to the axis of the stipe, are distally
tapering or parallel-sided, and terminate in small hooks. Distal thecae overlap slightly,
become increasingly triangular in profile and about one-quarter the length is involved
in the hook. Thecae number 10 to 8 in 10 mm, and are 0.5 m high proximally and at
least 1.4 mm high distally.
Discussion
The Yukon occurrence of the species appears to be slightly younger than the
occurrence in Scania (Tornquist, 1899), the Lake District (Hutt, 1975), Germany
(Schauer, 1971), and Bornholm (Bjerreskov, 1975).
The specimens from Peel River and Tetlit Creek, which were tentatively identified
as M. decipiens, differ from the typical species in possessing fewer, more widely
spaced and slightly shorter rastritiform thecae, as well as more distinctly triangular
distal thecae.
Monograptus decipiens valens (Pribyl and Minch, 1942)
Bigs= 0G; Ile. 238, DEG
Demirastrites decipiens valens Pribyl and Munch, 1942: 14.
Monograptus decipiens, Elles and Wood, 1913: 469 (pars).
Demirastrites decipiens valens, Munch, 1952: 128.
Demirastrites decipiens valens, Golikov, 1973: 43.
Occurrence
Sedgwicki, and lower part of the turriculatus zones, Peel River, at 516.3, 516.9,
517.9, 518.8, and 521.8 m; and Blackstone River, at 80.2, 83.8, 85.3, 88.7, and
89 m.
Material
The species is common to abundant and preservation ranges from moderate to good.
Illustrated specimens are ROM 38757 to 38759 and 38917 to 38919.
Description
The rhabdosome is moderately to strongly dorsally curved proximally, less so
distally, but coils through at least one complete volution. In large specimens, distal
75
portions of the stipe may undergo torsion, so that the thecae are on the convex side.
The sicula is 1.1 to 1.2 mm long, its apex is level with the tip of theca 1 and it is
weakly ventrally curved.
The proximal two to three thecae are rastritiform, subtend an angle of about 70
degrees to the stipe, are weakly triangular in profile, and are hooked at their extreme
distal ends. The distal thecae are triangular and are progressively overlapped to a
maximum of about one-half their length. Rhabdosomal width ranges from 0.8 mm
proximally to 1.6 to 1.8 mm distally. Thecal spacing is nine to seven in 10 mm.
Discussion
This subspecies differs from M. decipiens decipiens with which it appears to
intergrade, in the possession of fewer rastritiform thecae, greater width and greater
overlap of distal thecae. Distal portions of the rhabdosome are very like those of M.
planus and M. planus obtusus, but M. decipiens valens differs in the possession of
distinct rastritiform proximal thecae. This subspecies is much more abundant in
Yukon than the typical form and its range appears to extend into younger beds.
Monograptus cf. denticulatus Tornquist, 1899
Figs. 6H, I, K; 24A, B
cf. Monograptus denticulatus Tornquist, 1899: 18.
Occurrence
Sedgwicki Zone, Peel River, at 519.4 m.
Material
Six incomplete, moderately well-preserved specimens on black shale. Illustrated
specimens are ROM 38760 to 38762.
Discussion
The Yukon specimens differ from most illustrations of M. denticulatus (cf. Elles and
Wood, 1913; Schauer, 1971; Hutt, 1975) in possessing only two rastritid proximal
thecae, the remainder being slightly overlapped. It is however, similar to specimens
described by Pribyl (1946) and to those illustrated by Bjerreskov (1975). M. ctf.
denticulatus from the Yukon differs from M. decipiens valens in possessing an only
gently curved distal portion of the rhabdosome, slightly overlapping distal thecae,
and more closely spaced thecae (11 to 8 in 10 mm). The rhabdosome width ranges
from 0.5 mm proximally to 1.4 mm distally.
76
Fig, 19°4.c D.
A.
C.D.
B,F,G.
Lagarograptus ct. acinaces (Tornquist), Rock River, gregarius Zone
Collection at 249 m, ROM 38719; x 4.3.
Collection at 245 m, ROM 38718 and 38896: x 4.3.
Atavograptus strachani (Hutt and Rickards), acinaces Zone
B. Blackstone River, collection at 62.5 m, ROM 38721; x 2.6.
F. Peel River, collection at 460 m, ROM 38897; x 2.5.
G. Tetlit Creek, collection at 133 m, ROM 38723; x 4.2.
Lagarograptus inexpeditus Obut and Sobolevskaya, Peel River, collection at
481.9 m, triangulatus Zone?, ROM 38898; x 3.6.
Atavograptus cf. gracilis Hutt, Rock River, collection at 249 m, gregarius Zone, ROM
38899; x 4.6. (Note: top end of H continues on lower end of I.)
77
Fig. 20 a. Pribylograptus angustus (Rickards), Peel River, collection at 488 m, magnus Zone?,
ROM 38746; x 5.6.
B-D. Coronograptus gregarius gregarius (Lapworth), Peel River
B. Collection at 488 m, magnus Zone?, ROM 38714; x 5.4.
C,D. Collection at 465.1 m, gregarius Zone, ROM 38716 and 38900; x 4.9, x 4.8.
E,l. Coronograptus hipposideros (Toghill), Peel River, collection at 471.5 m, gregarius
Zone, ROM 38728 and 38729; x 7.2, x 4.0.
F,G,H,J. Coronograptus gregarius arcuatus Obut and Sobolevskaya, gregarius Zone
F,H. Peel River, collection at 470.3 m, ROM 38901 and 38902; both x 4.7.
G. Tetlit Creek, collection at 136 m, ROM 38903; x 3.6.
J. Peel River, collection at 474 m, ROM 38904; x 3.4.
78
The distal thecae of the Yukon specimens are in the shape of deceptively simple
hooks. The reason for the simple profile appears to lie in the fact that, upon
compression, the distal hooked and twisted portions of the thecae are folded under,
and partially hidden by, the main portion of the thecae.
Monograptus cf. elongatus Tornquist, 1899
Figs. 60; 24)
cf. Monograptus elongatus Tornquist, 1899: 17.
Occurrence
Triangulatus Zone, Peel River, at 477 m.
Material
Proximal portions of three relatively poorly preserved specimens on black shale. The
illustrated specimen is ROM 38765.
Description
The rhabdosome is very delicate, and its proximal region is weakly dorsally curved
and straight thereafter. The sicula is very narrow and about 0.8 mm long. The thecae,
which number eight to seven in 10 mm, overlap only slightly; the long prothecal
portions are inclined at a very low angle to the axis of the stipe and the metathecal
portions, which comprise about one-quarter the total length, are sharply hooked. The
rhabdosome widens imperceptibly from 0.25 mm across theca 1, to an observed
maximum of 0.5 mm distally.
Discussion
The specimens from the Yukon appear to differ from the types only in possessing
somewhat more widely spaced thecae. The lack of adequate illustrations of the thecae
in Tornquist (1899) prevents a positive identification from being made.
Monograptus exiguus primulus Boucek and Pribyl, 1942
Figs. 7A, D, F, G; 24C-F, K
Monograptus (Streptograptus) exiguus primulus Boucek and Pribyl, 1942: 7.
Streptograptus exiguus primulus, Munch, 1952: 111.
Monograptus (Streptograptus) exiguus primulus, Schauer, 1971: 71.
Monograptus exiguus primulus, Bjerreskov, 1975: 62.
19
Occurrence
Turriculatus Zone, Peel River, at 516.9, 517.9, 518.8, 523, 528.8, 531.9, 536.1,
544.4, 548.9, 553.8, and 559.3 m; Blackstone River, at 91.4, 92.7, 94.8, and 99 m;
Tetlit Creek, at 148 m; Rock River, at 287, 293, and 302 m; Mount Sekwi, at
527.6 m; Delorme Range, at 804.7 m.
Material
Hundreds of specimens, ranging from poorly to moderately well-preserved, as carbon
films on black shale. Illustrated specimens are ROM38766 to 38769 and 38920 to
38922.
Description
The rhabdosome is small, delicate, hook-shaped, strongly to moderately ventrally
curved to about the level of theca 5, then decreasing to gentle curvature thereafter.
The extreme proximal portion of the rhabdosome, involving the sicula and the first
two thecae, may be straight or weakly dorsally curved. The sicula is 0.9 to 1.0 mm
long, and its apex is level with the tip of theca 2.
The thecae are enrolled and apparently undergo considerable torsion, so that the
aperture projects laterally. The enrolled part of the thecae represents about one-half
the total length of the theca and occupies one-third proximally, and one-half dorsally,
of the stipe width. Thecal number ranges from 12 in 10 mm proximally to 8 to 10 in
10 mm distally, depending on the length of the rhabdosome. The rhabdosome widens
very gradually from 0.45 to 0.5 mm proximally to a maximum distal width of
0.8 mm.
Discussion
The separation of M. exiguus exiguus and M. e. primulus is based on the rhabdosomal
width and thecal spacing. In the typical subspecies, they are 0.5 mm and 14 to 16 in
10 mm, respectively (Bjerreskov, 1975), while in M. exiguus primulus the width is
0.8 mm (0.9 mm according to Bjerreskov, 1975; Hutt, 1975) and thecal spacing
ranges from 9 to 10 in 10 mm (Munch, 1952) to 11 to 12 in 10 mm (Bjerreskov,
1975). The Yukon specimens agree well with M. exiguus primulus in thecal spacing
and stipe width.
Monograptus falx (Suess, 1851)
Figs. 7N, P, Q; 24G-I
Graptolithus falx Suess, 1851: 35.
Spirograptus falx, Pribyl, 1944: 216.
Spirograptus falx, Munch, 1952: 117.
80
Occurrence
Turriculatus and spiralis zones, Peel River, at 523, 544.4, and 611.4 m; and
tentatively Whittaker Range, at 856.5 m.
Material
Several moderately to well-preserved specimens from each collection. Illustrated
specimens are ROM 38780 to 38782.
Description
The rhabdosome is small, moderatély dorsally curved in the proximal region and
gently curved dorsally in the distal region. Stipe width ranges from 0.5 to 0.7 mm
across theca 1, to a maximum distal width of 1.0 mm. The sicula is 1.0 to 1.1 mm
long and its apex is almost level with the distal end of theca 1.
The thecae overlap only slightly, the prothecal portions are consistently inclined
about 30 degrees to the stipe axis and the metathecae, which comprise about one-third
the total length of the thecae, have the shape of broad, prominent hooks similar in
nature to those in M. tullbergi tullbergi. Additionally, the metathecae appear to have
been asymmetric and to have undergone torsion exactly as do those of M. tullbergi?
in Bjerreskov, (1975: 65, fig. 19c). The thecae occupy one-half to two-thirds of the
stipe width and are spaced at the rate of 8 to 10 in 10 mm throughout the length of the
rhabdosome.
Discussion
This is the first report of M. falx from outside Europe. As was pointed out by Pribyl
(1944), this species is very similar to M. tullbergi in thecal characteristics. M. falx
differs from M. tullbergi in its lesser distal and proximal width and by the lack of
narrow, protracted proximal end. The Yukon specimens differ from those from
Czechoslavakia only in being longer.
Monograptus flagellaris Tornquist, 1892
Fig. 7E
Monograptus flagellaris Tornquist, 1892: 42.
Monograptus flagellaris, Elles and Wood, 1913: 457.
Spirograptus flagellaris, Munch, 1952: 116.
Occurrence
Turriculatus Zone, Blackstone River, at about 91.4 m (specimen from an old
81
collection and difficult to correlate with the writer’s 1977 collection); and from
Clearwater Creek, at 67.1 and 68.6 m.
Material
Several incomplete, moderately well-preserved specimens on black shale. The
illustrated specimen is ROM 38772.
Discussion
The incompleteness of the Yukon specimens prevents accurate assessment of their
morphology. The specimens are similar to M. flagellaris Tornquist (1892) and to M.
drepanoformis Toghill and Strachan (1970). According to Toghill and Strachan
(1970), M. drepanoformis is distinguished from M. flagellaris by its hooked, rather
than coiled, distal thecae. Although incomplete, the Yukon specimens possess coiled
thecae.
The thecae number about 10 in 10 mm distally and the maximum width of the
rhabdosome is 1.1 mm.
The Yukon occurrence of M. flagellaris in the turriculatus Zone is older than is
typical elsewhere (spiralis Zone, or equivalent). Etherington (1967) previously
reported M. flagellaris from the turriculatus Zone of Clearwater Creek, and this is
confirmed in this study.
Monograptus involutus Lapworth, 1876
Figs, 7B,¢;) 254.5, @
Monograptus intermedius var. involutus Lapworth, 1876: 317.
Monograptus involutus, Elles and Wood, 1913: 478.
Spirograptus involutus, Pribyl, 1944: 204
?Demirastrites delicatulus, Obut and Sobolevskaya, 1968: 109.
Monograptus (Spirograptus) involutus, Schauer, 1971: 72.
Monograptus involutus, Hutt, 1975: 91.
Oktavites involutus, Golikov, 1976: 36
?Monograptus changyangensis, Chen and Lin, 1978: 61.
Occurrence
Magnus Zone?, Peel River, at 485.9, 487.4, and 488 m; and argenteus Zone,
Blackstone River, at 65.5 m.
Material
The species is uncommon in any collection, is seldom complete, and few specimens
82
Fig. 21 A-c_ Pristiograptus regularis (Tornquist), Peel River, turriculatus Zone
E,K.
G;HY,L-
A,B. Collection at 521.8 m, ROM 38905 and 38739; x 2.6.
c. Collection at 523 m, ROM 38906; x 2.9.
Pristiograptus nudus (Lapworth), Peel River, collection at 523 m, turriculatus Zone,
ROM 38743; x 3.0.
Monograptus clingani (Carruthers), convolutus Zone
E. Peel River, collection at 507.8 m, ROM 38748; x 2.2.
K. Blackstone River, collection at 70.4 m, ROM 38907; x 2.4.
Monograptus cf. argenteus (Nicholson), Peel River, collection at 491.4 m, argenteus
Zone, ROM 38747; x 2.1.
Monograptus communis Lapworth, Peel River, convolutus Zone
G,H,L. Collection at 496.2 m, ROM 38735, 38908, and 38736; x 2.6, x 2.1, Xx 2.6.
J. Collection at 498.7 m, ROM 38909; x 2.9.
Monograptus circularis Elles and Wood, Peel River, collection at 513.6 m, sedgwicki
Zone, ROM 38910; x 7.2.
84
B,E.
(GD).
Monograptus convolutus (Hisinger), convolutus Zone
A. Peel River, collection at 498.7 m, ROM 38752; x 3.4.
F. Blackstone River, collection at 70.4 m, ROM 38911; x 2.6.
Monograptus aff. cygneus Tornquist, (sensu Obut and Sobolevskaya, 1967), Peel
River, convolutus Zone
B. Collection at 512.8 m, ROM 38753; x 4.1.
E. Collection at 498.7 m, ROM 38912; x 2.4.
Monograptus curvus Manck, Peel River, collection at 611.4 m, spiralis Zone, ROM
38913 and 38750; x 2.9.
are well preserved. Illustrated specimens are ROM 38770 to 38771 and 38923 to
38924.
Description
The rhabdosome is delicate and irregularly to apparently planispirally coiled through
at least two volutions. Stipe width increases slowly from 0.5 mm across theca | to a
maximum of at least 0.9 mm distally, inclusive of thecal ‘‘spines’’. The sicula is
small, 0.9 to 1.1 mm long and its apex is level with the tip of theca 1.
The thecae number 10 to 8 in 10 mm and overlap no more than one-third their
length distally. They consist of long, triangular prothecae inclined about 20 degrees
to the axis of the stipe and short, sharply hooked metathecae. The metathecal beaklike
profile is accented by a ventral projection of possibly transversely projecting
‘*spines’’.
Discussion
The delicate, spiralled rhabdosome, and the thecae with relatively long, inclined
prothecae and short, sharply hooked metathecae with ‘‘spines’’ are features typical of
this species. The Yukon specimens show the spiralled nature of the species perhaps
better than most published illustrations, as well as clearly showing the presence of the
thecal “*spines’’. Hutt (1975) states that the sicula is 0.6 mm long in her material,
although Schauer (1971) notes the presence of a 1.0 mm long sicula, a length more in
accord with that of the Canadian specimens.
M. calamistriatus described from Alaska by Churkin and Carter (1970) is similar to
M. involutus but is more robust and possesses much more closely spaced thecae.
Obut and Sobolevskaya (1968) describe Demirastrites delicatulus from the
triangulatus Zone of northern Siberia. Their specimens are spirally coiled and the
thecae possess short, sharply hooked metathecae. A close examination of their
illustration (Obut and Sobolevskaya, 1968: fig. 7, pl. 30) clearly shows the presence
of thecal “‘spines’’. This species might be better assigned to M. involutus.
M. changyangensis Sun, illustrated in Chen and Lin (1978), appears to be identical
to M. involutus. Hutt (1975) has placed the two species in synonymy, a practice
tentatively followed in this study.
Monograptus cf. knockensis Elles and Wood, 1913
Figss./K: 251
cf. Monograptus knockensis Elles and Wood, 1913: 462.
Occurrence
Turriculatus Zone, Blackstone River, at 80.2 m.
Material
A single, incomplete, poorly preserved and flattened specimen on black shale. The
illustrated specimen is ROM 38777.
Discussion
The specimen from Blackstone River, although difficult to assess, is nevertheless
sufficiently exceptional to warrant a comment. Its thecae are without overlap, number
six in 10 mm (compared with 8 in 10 for material of M. knockensis described by
Rickards [1970] and Hutt [1975]) and, because of an apparent sharp reverse
curvature of the metathecae, the metathecae are almost parallel to each other. The
stipe is 1.0 mm wide.
Monograptus lobiferus harpago Tornquist, 1899
Fics 27: 256k
Monograptus harpago Tornquist, 1899: 16 (pars).
Monograptus lobiferus harpago, Bjerreskov, 1975: 67.
Occurrence
Convolutus Zone, Peel River, at 502.3 _m and possibly 507.8 m; tentatively
turriculatus Zone, Clearwater Creek, at 65.5 m.
Material
About a dozen poorly to moderately well-preserved specimens from the 502.3 m
collection, and a few specimens from each of the other two collections. Illustrated
specimens are ROM 38775 to 38776 and 38925 to 38926.
Description
The rhabdosome is gently curved dorsally for the distance of the first three to four
thecae, then very gently curved ventrally to the level of thecae 10 to 12, and thereafter
generally straight. Rhabdosomal width is 0.5 mm across theca 1, increasing
moderately rapidly to about 1.0 mm at the level of theca 10 and thereafter gradually
to a maximum of 1.5 mm ina specimen which is more than 70 mm long. The sicula
is 1.3 to 1.4 mm long.
The thecae are in contact only proximally and overlap slightly distally; they occupy
at least one-half the stipe width and number eight to six in 10 mm. The proximal
thecae are moderately hooked, whereas distal thecae become progressively more
strongly hooked and lobate, so that apertures appear to be directed dorsally. The
86
proximal thecae are consistently spinose, while spines are only sporadically seen on
distal thecae; the spines presumably were laterally directed.
Discussion
The distinction between M. lobiferus lobiferus and M. |. harpago was discussed fully
by Bjerreskov (1975), who also suggested that M. knockensis Elles and Wood is
probably a junior synonym of M. lobiferus harpago. Examination of the types of M.
knockensis shows that the metathecae are completely folded back and that the
apertures appear to be directed proximodorsally. M. knockensis is apparently a valid
species.
Monograptus marri Perner, 1897
Figs 8D); 20A=D
Monograptus Marri Perner, 1897: 21.
Monograptus Marri, Elles and Wood, 1913: 422.
Monograptus marri, Obut and Sobolevskaya, 1965: 46.
Monograptus marri, Hutt et al, 1970: 9.
Monograptus marri, Hutt, 1975: 95.
Monograptus marri, Bjerreskov, 1975: 69.
Occurrence
Common in the turriculatus Zone, and less common in the spiralis Zone. Found at
Peel River, at 548.9 and 553.8 m; Rock River, at 293, 302, 323, and 326 m, and
tentatively from 306, 309, and 315 m; and Blackstone River, at 92.7 and 94.8 m, and
tentatively from 91.4 m.
Material
A few poorly to moderately well-preserved specimens from each collection.
Illustrated specimens are ROM 38786 to 38787 and 38923 to 38924.
Description
The rhabdosome is longer than 50 mm and, except for a gentle dorsal curvature for
the distance of the first two thecae, is straight throughout its length. Rhabdosomal
width ranges from 0.5 to 0.6 mm across theca 1 and increases gradually to a
maximum distal width of 1.4 to 1.6 mm. The sicula is moderately stout, 1.4 to
1.5 mm long, and its apex attains the level of the tip of theca 2.
The thecae are of the priodon type, although the metathecae are more strongly
87
curved than typical of that species and, as a result, the apertures are directed
proximally. Thecal overlap ranges from only slightly proximally to about one-third
distally, and the free portion of the thecae occupy about one-half the stipe width; they
number 9 to 10 in 10 mm proximally and 8 to 9 in 10 mm distally.
Discussion
The narrow rhabdosome and proximally directed thecal apertures are characteristic of
the species. Thecal spacing of the Yukon specimens is slightly less than typical,
although it is similar to that of the Taimyr specimens (Obut et al., 1965).
Monograptus millepeda (M’Coy, 1850)
Figs: 7MyO225D, Gi
Graptolites millepeda M’Coy, 1850: 270.
Monograptus millepeda, Tornquist, 1892: 18.
Monograptus millepeda, Elles and Wood, 1913: 465.
Campograptus curtus Obut and Sobolevskaya, 1968: 104.
Monograptus millepeda, Hutt, 1975: 96.
Occurrence
Argenteus Zone, Peel River, at 491.4 m; Tetlit Creek, at 129 m; and Blackstone
River, at 65.5 m. Tentatively from the turriculatus Zone of Blackstone River, at
86.9 m.
Material
A few moderately well-preserved specimens in each of the three collections.
Illustrated specimens are ROM 38778 to 38779 and 38927 to 38928.
Description
The rhabdosome is very strongly dorsally curved in its proximal region, decreasing to
gently curved distally; rhabdosomal width ranges from about 0.8 mm across theca |
to a maximum distally of 1.4 to 1.5 mm. The sicula is not clearly discernible, but
appears to be about 1.0 m long.
The thecae are triangular in profile, overlap only slightly, and possess prominently
hooked and large metathecae which occupy one-half the stripe width distally; thecal
apertures face the ventral wall. The thecae number about 12 to 10 in 10 mm
proximally and eight in 10 mm distally.
88
Fig. 23 A,Cc.F. Monograptus decipiens decipiens Tornquist, Blackstone River, collection
sedgwicki Zone, ROM 38914, 38915, and 38916; all x 3.2.
B,D.E,G. Monograptus decipiens valens (Pfibyl and Minch), turriculatus Zone
B.
a
Blackstone River, collection at 83.8 m, ROM 38917; x 2.6.
Peel River, collection at 521.8 m, ROM 38918; x 4.0.
Blackstone River, collection at 88.7 m, ROM 38759; x 2.8
Blackstone River, collection at 85.3 m, ROM 38919; x 2.6
at 76.2 m,
89
G-I.
J.
90
Monograptus cf. denticulatus Tornquist, Peel River, collection at 519.4 m, sedgwicki
Zone, ROM 38760 and 38761; both x 4.0.
Monograptus exiguus primulus Bouéek and Pribyl, turriculatus Zone
c. Peel River, collection at 531.9 m, ROM 38769; x 4.0.
D. Peel River, collection at 523 m, ROM 38920; x 4.2.
E. Peel River, collection at 536.1 m, ROM 38767; x 4.0.
F. Rock River, collection at 287 m, ROM 38921; x 5.2.
K. Peel River, collection at 553.8 m, ROM 38922; x 3.0.
Monograptus falx (Suess), Peel River
G. Collection at 544.4 m, turriculatus Zone, ROM 38782; x 2.9.
H,I. Collection at 611.4 m, spiralis Zone, ROM 38781 and 38780; both x 3.7.
Monograptus cf. elongatus Tornquist, Peel River, collection at 477 m, triangulatus
Zone, ROM 38765; x 5.3.
Discussion
The Yukon specimens are very similar to the types of M. millepeda except that they
possess slightly fewer thecae. As is the case with the European occurrences, those of
the Yukon are confined to the argenteus Zone.
Monograptus minimus Bouéek and Pribyl, 1951
Figs. 8A; 26H
Monograptus (Mediograptus) minimus Boucek and Pribyl, 1951: 200.
Occurrence
Sakmaricus-laqueus Zone, Rock River, main branch, collections 3F and 4F.
Material
Several specimens from each collection, moderately well-preserved on black,
calcareous shale. Illustrated specimens are ROM 38783 and 38934.
Description
The rhabdosome is delicate, moderately curved in a dorsal direction proximally and
becoming straight distally. The sicula is prominent, 1.4 to 1.5 mm long and 0.3 mm
wide, and almost attains the level of the tip of theca 2. Rhabdosomal width ranges
from 0.25 mm at theca | to a maximum of 0.45 mm distally.
The thecae are long with the prothecal portions parallel to the stipe axis and the
metathecal portions coiled into lobes which occupy one-third to one-half the stipe
width. The thecae number 10 in 10 mm.
Discussion
The Yukon specimens are intermediate in their thecal spacing between that of the M.
minimus minimus (11 to 12 in 10 mm) and M. minimus cautleyensis (nine in 10 mm:
Rickards, 1965; Bjerreskov, 1975). The length of the sicula in the study specimens
compares well with Boucek and Pribyl’s (1951) description of ‘‘relatively fairly
long’’, and Yukon specimens are assigned to M. minimus minimus Boucek and
Pribyl.
Monograptus cf. mirus Perner, 1897
Fig. 26)
cf. Monograptus mirus Perner, 1897: 26.
9]
Occurrence
Sedgwicki Zone, Peel River, at 515.1 and 519.4 m.
Material
Six poorly preserved specimens on black shale. The illustrated specimen is ROM
38935:
Discussion
This species bears an overall similarity to M. involutus but differs in that the proximal
portion of the overall spiralled rhabdosome is generally curved in a direction opposite
to that of the remainder of the rhabdosome, resulting in a nooselike proximal portion.
Additionally, the thecae overlap only very slightly, the metathecae are sharply
recurved into short hooks without spines, and the rhabdosome is more delicate overall.
Thecae number nine to seven in 10 mm and stipe width ranges from about 0.5 mm
proximally to about 0.75 mm distally.
M. mirus has been described, only inadequately, by Perner (1895), Waterlot
(1945), and Minch (1952). Pribyl’s (1944) description although agreeing with that of
the Yukon specimens, is without accompanying illustrations.
Monograptus cf. pandus Lapworth, 1877
Bisa, 8B. eC
cf. Monograptus lobiferus var. pandus Lapworth, 1877: 129.
Occurrence
Turriculatus Zone, Peel River, at 531.9, 536.1, and 544.4 m, and possibly 559.3 m.
Material
One to several specimens in each collection, poorly to moderately well-preserved on
black shale. Illustrated specimens are ROM 38784 to 38785.
Discussion
The relatively small proportion (one-quarter to one-fifth) of the rhabdosome occupied
by the thecal hooks and the close proximity of the thecal apertures to the preceding
thecae are characteristic of the species. The maximum width observed in incomplete
a7
specimens is 2.0 mm. Sicula length is about 1.6 mm. Thecae number 10 to 11 in 10
mm proximally and eight in 10 mm distally.
Monograptus parapriodon Boucéek, 1931
Figs. 8H, I; 26G, I
Monograptus parapriodon Boucek, 1931: 6.
Monograptus parapriodon, Munch, 1952: 100.
Monograptus (Monogr.) priodon parapriodon, Schauer, 1971: 57.
Monograptus parapriodon, Tsegel’nyuk, 1976: 241.
Occurrence
Sakmaricus-laqueus Zone, Peel River, at 635.5 m; Tetlit Creek, 216 m and possibly
213 m; main tributary of Rock River, collections 1F and 3F; and Mount Sekwi, at
384 m. It also occurs in lower Wenlock strata of Tetlit Creek, at 232 and 233 m.
Material
Few, poorly to well-preserved specimens in each collection. The illustrated
specimens are ROM 38790 to 38791.
Description
The rhabdosome is essentially straight throughout its length, although it may show
weak dorsal curvature for the distance of the first three thecae and very weak ventral
curvature about the level of theca 5. The proximal portion of the rhabdosome has a
generally delicate appearance and widens gradually from about 0.5 to 0.6 mm across
theca 1, to a maximum of 1.8 to 1.9 mm distally. The sicula is 1.3 to 1.4 mm long
and its tip is level with theca 1.
The thecae are of the priodon type throughout, but less of the length is involved in
the hooked portion that occupies about one-third to one-quarter the width of the
rhabdosome. Thecae number 10 to 11 in 10 mm proximally and 8 to 9 in 10 mm
distally.
Discussion
This species is very like M. priodon, but differs in being much more delicate
throughout its length and in possessing more widely spaced proximal thecae and less
strongly hooked thecal hoods. In some respects it resembles M. riccartonensis, but
does not possess the distinctive clawlike thecal profile. Specimens identified as M.
riccartonensis by Lenz (1974) are now placed in synonymy with M. parapriodon.
93
Monograptus planus planus (Barrande, 1850)
Pigs; 7H 26EEy Kk
Graptolithus proteus var. plana Barrande, 1850: 58.
Spirograptus planus, Pribyl, 1944: 227.
Monograptus planus, Sudbury, 1958: 524.
Monograptus (Spirograptus) planus planus, Schauer, 1971: 73.
Monograptus planus, Bjerreskov, 1975: 64.
Monograptus planus, Hutt, 1975: 99.
Oktavites planus, Sennikov, 1976: 201.
Occurrence
Turriculatus Zone, Peel River, at 523 m. Tentatively identified from Tetlit Creek, at
148 m, and Blackstone River, at 86.9 m.
Material
Four specimens, two moderately well-preserved on black shale. Illustrated specimens
are ROM 38773 to 38774 and 38932 to 38933.
Description
The rhabdosome is broadly dorsally curved through approximately 360 degrees, the
distal portion being less strongly curved. Width increases gradually from 0.4 to
0.5 mm across theca 1, to a maximum of 1.5 to 1.7 mm distally. The sicula is seen
on only one specimen and is 1.0 mm long.
The proximal thecae are long, the prothecal portions are inclined at a low angle, and
the metathecal portions form short, sharp hooks. The distal thecae are more
triangular, are inclined about 45 degrees to the axis of the stipe and are moderately
hooked, with hooks occupying one-half to one-third the stipe width; overlap is about
one-third. The thecae number 8 to 9 in 10 mm proximally and about eight in 10 mm
distally.
Discussion
Hutt (1975) has remarked on the number of axially elongated thecae in her
specimens. The Yukon species bear five to six axially elongated thecae, and are thus
like those of Hutt (1975) and Bjerreskov (1975), but differ in this respect from those
of Sudbury (1958) or Sennikov (1976).
94
Fig. 25 A,B,E.
(Ae
D,G,H.
Monograptus involutus Lapworth, Peel River, magnus Zone?
A,B. Collection at 488 m, ROM 38770 and 38923; x 5.4, x 5.5.
E. Collection at 487.4 m, ROM 38924; x 5.1.
Monograptus lobiferus harpago Tornquist, Peel River, collection at 502.3 m,
convolutus Zone, ROM 38925 and 38926; x 2.6, x 1.7.
Monograptus millepeda (M’Coy)
D,H. Peel River, collection at 491.4 m, argenteus Zone? ROM 38927 and 38778; x
Bi), Ke S59
G. Monograptus cf. millepeda (M’Coy), Blackstone River, collection at 86.9 m,
turriculatus Zone, ROM 38928; x 5.5.
Monograptus cf. knockensis Elles and Wood, Blackstone River, collection at 80.2 m,
turriculatus Zone, ROM 38777; X 5.6.
Fig. 26 A-D. Monograptus marri Perner, turriculatus Zone
96
EA EKe
G,I.
A.D. Peel River, collection at 553.8 m, ROM 38929, and 38930; x 3.0.
B. Peel River, collection at 548.9 m, ROM 38787; x 4.2.
Cc. Rock River, collection at 293 m, ROM 38931; x 4.2.
Monograptus planus planus (Barrande), turriculatus Zone
E,F. Peel River, collection at 523 m, ROM 38932 and 38774; x 2.6, x 5.0.
K. Blackstone River, collection at 86.9 m, ROM 38933; x 3.0.
Monograptus parapriodon Boucek, sakmaricus-laqueus Zone
G. Rock River, main branch, collection 3F, ROM 38790; x 2.0.
1. Peel River, collection at 635.5 m, ROM 38791; x 3.2.
Monograptus minimus Boucek and Pribyl, Rock River, main branch, collection 3F,
sakmaricus-laqueus Zone, ROM 38934; x 4.5.
Monograptus cf. mirus Perner, Peel River, collection at 519.4 m, sedgwicki Zone,
ROM 38935; x 3.3.
Monograptus planus obtusus Schauer, 1971
Figs. 8M; 27A, G
Monograptus (Spirograptus) planus obtusus Schauer, 1971: 74.
Occurrence
Turriculatus Zone, Peel River, at 531.9 m; and Blackstone River, at 91.4 m.
Material
Six poorly preserved specimens from Blackstone River, and five moderately
well-preserved specimens from Peel River. Illustrated specimens are ROM 38795 to
38936.
Description
The sicula appears to be about 0.8 mm long, thecae are spaced at the rate of 11 to 12
in 10 mm proximally and 9 to 10 in 10 mm distally, and the rhabdosome width
ranges from 0.4 to 0.5 mm across theca 1, to a maximum distal width of 1.5 to
1.6 mm.
Discussion
The rhabdosome of the study material possesses the characteristic arcuate shape of M.
planus obtusus and distal thecae are identical. The thecae of some specimens clearly
show the torsion and hooking of the distal thecae. The subspecies differs from M.
planus planus in its much more robust proximal portion, in which laterally elongated
thecae number only two to three, and in that the thecal hooks occupy about one-half
the stipe width throughout.
Monograptus priodon (Bronn, 1835)
Fig. 28A
Lomatoceras priodon Bronn, 1835: 56.
For detailed synonymy, see Schauer, 1971: 56—57.
Occurrence
Rare and identified tentatively in the turriculatus Zone, and common in the spiralis
and sakmaricus-laqueus zones. Peel River, at 559.3?, 570.9, 579.7, 614.2, 615.7,
97
629.4, 630.9?, 635.5?, and 638.6 m; Blackstone River, at 91.47, and 103.8 m; Tetlit
Creek, at 148?, 185?, 187?, 220, and 223 m; Mount Sekwi, at 384 m; Whittaker
Range, at 798.6?, 802.87, 805.3, 814.4, 815.9, 8237, 827.5, 836.7, 844.3, 892.5,
896:1, 900.77, 905.375 910: 7,915.97, and 922 m:; Delonme Range, atl 906,85 911.4.
912.3, and 935.7 m; Rock River, collections 1F, 4F, 5F?, 6F, 7F, 8F?, 9F, 10F?,
and 11F?; and Clearwater Creek, at 76.2, 79.2, 83.8, 86.9, 89.9 and 93 m.
Material
Hundreds of poorly to moderately well-preserved specimens. The illustrated
specimen is ROM 38941.
Discussion
M. priodon is the most ubiquitous and one of the commoner monograptids in
northern Canada. The species is well documented from around the world; its
characteristic features are well known and are not described here. Lenz (1974)
documented the evolutionary development within M. priodon. The species is
particularly well respected in the upper Llandovery and lower Wenlock strata of the
Cape Phillips Formation, Arctic Islands, where it has been recovered in abundance in
uncompressed form.
Monograptus proteus (Barrande, 1850)
Figs. 8S, T27 Curl
Graptolithus proteus Barrande, 1850: 58.
Monograptus proteus, Elles and Wood, 1913: 477.
Monograptus proteus, Hutt, et al., 1970: 12.
Monograptus (Spriograptus) proteus proteus, Schauer, 1971: 75.
Monograptus proteus, Bjerreskov, 1975: 65.
See Rickards, 1970, for a detailed synonymy to 1970.
Occurrence
Turriculatus and lower part of the spiralis zones. Collected from Peel River, at 523
and 559.3 m, and tentatively 519.4 and 541.3 m; Rock River, at 287, 293, and
302 m, and possibly 323 and 326 m; and Mount Sekwi, at 547.4 m and possibly
527.6 m; and from Blackstone River, at 92.7, 94.8, and 99 m.
Material
Specimens fairly to moderately well-preserved on black shale; abundant at Rock
River, common at other localities. Illustrated specimens are ROM 38801 to 38802 and
98
38938. Additionally, an illustrated specimen identified as M. cf. proteus (Fig. 271) is
numbered ROM 38939.
Description
The rhabdosome is helically coiled in a loose open spiral and, depending on
orientation upon compression, is preserved as either a loose spiral, or as an S-shaped
pattern. The proximal portion of the rhabdosome is thin and very delicate, measuring
0.25 mm across theca 1; distal portions become much more robust and attain a
maximum width of 2.0 mm. The sicula is about 1.0 mm long.
The proximal thecae are very slender and axially elongate; prothecal portions are
inclined at very low angles to the stipe, whereas the metathecal portions are short,
sharp hooks which undergo torsion and comprise only about one-seventh or
one-eighth of the thecal length. Distal thecae are much more distinctly triangular,
overlap about one-third their length, and thecal hooks comprise about one-third of the
thecal length.
The thecae occupy about one-half the stipe width proximally and about two-thirds
the width distally; they number eight in 10 mm proximally and 10 to 12 in 10 mm
distally.
Discussion
The spacing of the distal thecae in the Yukon specimens is identical to that of the type
species and differs in this respect from the material described by Elles and Wood
(1913) and Bjerreskov (1975). The torsion of the thecae is clearly shown in the
specimens illustrated by Hutt et al. (1970: pl. 26, fig. 4) and Bjerreskov (1975: fig
19B), but is visible on only a few of the study specimens.
Monograptus pseudobecki Boucek and Pribyl, 1942
Bigs. 8). iKo ik 286,
Monograptus Becki, Lapworth, 1876: 500.
Monograptus Becki, Elles and Wood, 1913: 452.
Monograptus (Streptograptus) pseudobecki Bouéek and Pribyl, 1942: 18.
Monograptus pseudobecki, Rickards, 1970: 78.
Monograptus (Streptograptus) runcinatus pseudobecki, Schauer, 1971: 71.
Monograptus pseudobecki, Bjerreskov, 1975: 63.
Occurrence
Sedgwicki and turriculatus zones, Peel River, at 519.4 and 523 m; and tentatively
Blackstone River, at 74.7, 83.8, 85.3, 86.9, and 88.7 m.
99
Material
Rare to common, poorly to moderately well-preserved specimens on black shale.
Illustrated material is ROM 38787, 38792 to 38794, and 38943.
Description
The rhabdosome is S-shaped, with the proximal portion dorsally, and the distal
portion ventrally, curved. Width is about 0.5 mm across theca 1 and increases
gradually to a maximum of 1.1 mm. The sicula is seen in only one specimen and
appears to be 1.2 mm long.
The prothecal portions of the thecae are elongate, overlap only slightly, and are
parallel to the axis of the stipe. The metathecal portions of the thecae are tightly
coiled to form a lobe which occupies at least one-half the width of the stipe. The
thecae number 10 to 11 in 10 mm proximally and seven to nine in 10 mm distally.
Discussion
Although seen in only a single fragment, the Yukon specimen appears to differ from
the European representatives only in the length of the sicula. Rickards (1970)
describes a sicula length of 0.78 mm, whereas Bjerreskov (1975) lists 0.8 mm.
Monograptus revolutus Kurck, 1882
Figs:.10D, Ki L28B,.D.4H
Monograptus revolutus Kurck, 1882: 299.
Monograptus revolutus, Hutt, 1974: 197.
Monograptus revolutus, Bjerreskov, 1975: 51.
Occurrence
Gregarius, argenteus, triangulatus, and possibly the magnus? zones. Peel River, at
468.2, 471.5, 482.5, and 488 m, and tentatively at 470.3, 474, and 487.4 m; and
Blackstone River, at 65.5 m.
Material
Common in Blackstone River collection, rare in other collections. Preservation of
specimens ranges from poor to moderately good; all are incomplete and without
sicular ends. Illustrated specimens are ROM 38825 to 38827 and 38942.
Description
The rhabdosome is dorsally and uniformly curved throughout its length, but more
100
Fig. 27 AG.
BEF:
GH
Monograptus planus obtusus Schauer, Peel River, collection at 531.9 m, turriculatus
Zone, ROM 38795 and 38936; both x 4.6.
Monograptus sidjachenkoi (Obut and Sobolevskaya), Peel River, convolutus Zone
B. Collection at 512.8 m, ROM 38798; x 4.0.
E. Collection at 496.2 m, ROM 38937; x 2.5.
F. Collection at 507.8 m, ROM 38797; x 4.6.
Monograptus proteus (Barrande)
Cc. Rock River, collection at 287 m, turriculatus Zone, ROM 38802, x 5.2.
H. Peel River, collection at 523 m, turriculatus Zone, ROM 38938; X 2.6.
1. Monograptus cf. proteus (Barrande), Peel River, collection at 519.4 m,
sedgwicki Zone?, ROM 38939; x 3.5.
Monograptus cf. tenuissmus (Obut and Sobolevskaya), Peel River, collection at
519.4 m, sedgwicki Zone?, ROM 38940; x 4.1. 101
102
CIE.
Monograptus priodon (Bronn), Mount Sekwi, collection at 384 m, sakmaricus-
laqueus Zone?, ROM 38941; x 4.2.
Monograptus revolutus Kurck, Peel River
B,D. Collection at 471.5 m, gregarius Zone, ROM 38942 and 38826; x 3.0, x 4.8.
H. Collection at 488 m, magnus Zone?, ROM 38825; x 4.0.
Monograptus pseudobecki Boucek and Pribyl, sedgwicki Zone
Cc. Blackstone River, collection at 74.7 m, ROM 38943; x 3.6.
E. Peel River, collection at 519.4 m, ROM 38787; x 2.5. (Also includes
Monograptus cf. denticulatus.)
Monograptus runcinatus richardsonensis subsp. nov., Blackstone River, collection at
94.8 m, turriculatus Zone, ROM 38944; x 3.7.
Monograptus austerus or M. revolutus, Peel River, collection at 470.3 m, gregarius
Zone, ROM 38945; x 3.0.
strongly in the proximal region. The proximal region is elongated and delicate in
appearance, but width increases relatively rapidly so that, from an initial width of
0.25 to 0.3 mm, the maximum width of 0.9 to 1.0 mm is quickly attained.
The proximal thecae are axially elongated and scarcely overlap; the prothecal
portions are inclined at a low angle; while the metathecal portions, which comprise
about one-quarter the thecal length, form a simple, but pronounced hook. Distal
thecae progressively increase their overlap and become essentially simple cylinders
which are inclined about 20 degrees and overlap about one-half. The thecal apertures
bear ‘‘horns’’ or lappets, which give an introverted profile to the thecae. Thecae
number seven to nine in 10 mm proximally and 8 to 10 in 10 mm distally.
Discussion
The study specimens are wider that those described by Hutt (1974) and Bjerreskov
(1975). In all other respects, however, they are very similar. M. revolutus 1s
distinguished from M. sudburiae by its lesser width and more delicate and protracted
proximal end.
Monograptus cf. revolutus Kurck, 1882
Fig. 28G
cf. Monograptus revolutus Kurck, 1882: 299.
Occurrence
Gregarius Zone, Peel River, at 470.3 m, and possibly from 485.9 m.
Material
A few poorly preserved, incomplete specimens on black shale. The illustrated
specimen is ROM 38945.
Discussion
In the absence of complete specimens, the distinction between M. austerus and M.
revolutus is nearly impossible. According to Hutt (1974-1975) the revolutus group
has introverted distal thecae, whereas those of the austerus group are simple tubes.
The study material consists of fragments with slender proximal ends and a gradually
widening stipe which attains a maximum width of 0.9 m. Proximal thecae are
strongly hooked and weakly overlapping, whereas distal thecae become progressively
less hooked and more strongly overlapping, and distal thecae are essentially simple
tubes. In some specimens distal thecae almost certainly have introverted apertures,
while in others this is not entirely clear. Thecae number eight to nine in 10 mm.
103
Monograptus rickardsi minor Hutt, 1975
Figs. 9F, G; 29A, B
Monograptus rickardsi minor Hutt, 1975: 103.
Occurrence
Turriculatus Zone, Rock River, at 287 m; and Peel River, at 528.5 m.
Material
Several specimens, one of which is nearly complete, well preserved on black shale.
[llustrated specimens are ROM 38808 to 38809.
Description
The rhabdosome is essentially straight throughout its length, except for a weak dorsal
curvature over the distance of the first three thecae and an extremely weak ventral
curvature about the level of theca 12. The rhabdosome width ranges from 1.2 to
1.3 m across theca 1, to a maximum (based on a single specimen only) of 2.0 mm
distally. The sicula is relat:vely robust, 1.3 to 1.6 mm long, and its apex attains the
level of the tip of theca 2.
The thecae are robust and strongly hooked, so that their apertures are directed
proximally; paired lateral processes are prominent on at least the proximal four to five
thecae. Distally, the thecae are more retroverted and beaklike. Thecae overlap only
slightly proximally and about one-third distally, and number 10 to 11 in 10 mm
proximally and eight in 10 mm distally (based on a single specimen).
Discussion
This subspecies is distinguished by the fact that the proximal thecae bear paired
spines. It differs from typical M. rickardsi by possessing more widely spaced thecae
and especially a much shorter sicula.
Monograptus runcinatus richardsonensis subsp. nov.
Figs. SHI. 20h 296.1, 5
Occurrence
Turriculatus Zone, Rock River, at 287 m; and Blackstone River, at 94.8 m.
104
Material
One moderately well-preserved specimen from Blackstone River, and about 10 fairly
to moderately well-preserved specimens from Rock River. Illustrated specimens
consist of ROM 38811 (holotype) and ROM 38810, 38812, 38944, and 38946
(paratypes).
Etymology
From the Richardson Mountains, northern Yukon.
Diagnosis
Rhabdosome S-shaped, with proximal portion moderately to strongly dorsally flexed.
Sicula 0.8 to 0.9 mm long. Rhabdosome 0.25 to 0.3 mm across theca 1, widening
steadily to about thecae 8 to 10, then very gradually to a distal maximum of 0.6 to
0.7 mm. Thecae lobate, retroverted, with a “‘sagging’’ profile, occupying
one-quarter to one-third the stipe width, and numbering 12 to 13? in 10 mm
proximally and 10 in 10 mm distally.
Description
The rhabdosome is moderately to strongly dorsally curved through an arc ranging
from 30 degrees to greater than 90 degrees over the distance of the first three to four
thecae, then weakly ventrally curved in the region of thecae 5 to 8 and straight to
gently undulating thereafter.
The prothecae are elongate and parallel, or weakly inclined to, the stipe axis,
whereas the metathecae are tightly coiled, lobate and, although not clearly seen in
most specimens, clearly retroverted. The overall effect upon compression is to impart
a slightly sagging look to the thecal profile, so typical of M. runcinatus runcinatus.
Discussion
This subspecies bears an overall strong similarity to species such as M. psuedobecki,
M. capillaceous, and M. flexuosus, all but the first being from Wenlockian strata.
The nature of the thecae in the study specimens, that is the ‘‘sagging’ or ‘‘melted
candle wax’’ profile of the thecae due to compression of the retroverted metathecal
portions thecae, is, however, typical of M. runcinatus.
The subspecies differs from M. runcinatus runcinatus in possessing a much more
strongly dorsally flexed proximal region and in being only about one-half its width.
Monograptus cf. sartorius Tornquist, 1881
Figs; 9A-C;.29D, H
cf. Monograptus sartorius Tornquist, 1881: 441.
Occurrence
Turriculatus and the spiralis zones. Collected from Rock River, at 306, 309, and
326 m; possibly from Peel River, at 614.2, 629.4, and 637.3 m.
Material
Specimens mostly poorly preserved, common in collection from Rock River, 306 m,
rare in other collections. Illustrated specimens consist of ROM 38803 to 38805.
Description
The sicula of the Yukon specimens is 1.2 mm long and the thecae are spaced at the
rate of eight to nine in 10 mm proximally and seven to eight in 10 mm distally. The
rhabdosome ranges in width from 0.3 mm across theca | to a maximum of about
0.5 mm distally (0.6 mm if the very long Peel River specimen belongs in the same
species). The prothecae of the thecae are inclined about 15 degrees, while the
metathecae form single short and sharp hooks.
Discussion
The proximal portion of the study material is moderately strongly curved in a dorsal
direction, but because of the fragmentary state of the better preserved specimens, the
nature of the distal portion of the rhabdosome is unknown. A very long (120 mm) and
poorly preserved rhabdosome of what may be the same species from a collection
made at 614.2 m, Peel River, is dorsally curved proximally and gently but
consistently ventrally curved throughout its remaining length.
The study specimens resemble M. jacobseni Sherwin (1974) in rhabdosome shape
and dimensions and may be that species; Sherwin (1974), although, reports a straight,
as opposed to a dorsally, curved proximal portion to the rhabdosome.
Monograptus sedgwicki (Portlock, 1843)
Figs, 9D, E; 29E-G
Graptolithus (Prionotus) Sedgwickii Portlock, 1843: 318.
Monograptus Sedgwickii, Elles and Wood, 1913: 441.
Monograptus sedgwicki, Obut and Sobolevskaya, 1967: 97.
Monograptus (Monogr.) sedgwicki, Schauer, 1971: 55.
Monograptus sedgwicki, Hutt, 1975: 106
Occurrence
Sedgwicki and lower part of turriculatus zones. Collected from Peel River, at 513.6,
515.1, 516.3, and 521.8 m, and tentatively at 516.9 and 526 m; Blackstone River, at
72.2 and 76.2 m, and tentatively at 74.7 and 80.2 m.
106
Fig. 29 A,B.
(CEU
D,H.
E-G.
ESF:
G.
Monograptus rickardsi minor Hutt, Rock River, collection at 287 m, turriculatus
Zone, ROM 38808 and 38809; x 3.4, x 5.2.
Monograptus runcinatus richardsonensis subsp. nov., Rock River, collection
at 287 m, turriculatus Zone, ROM 38946, 38812, and 38811; all x 4.9.
Monograptus cf. sartorius Tornquist, Rock River, collection at 306 m,
spiralis Zone?, ROM 38803 and 38804; both x 5.2.
Monograptus sedgwicki (Portlock), sedgwicki Zone
Blackstone River, collection at 76.2 m, ROM 38947 and 38948; x 3.0.
Peel River, collection at 513.6 m, ROM 38807; x 4.2.
107
Fig. 30 A,Cc\F. Monograptus speciosus Tullberg, Tetlit Creek, collection at 217 m, sakmaricus-
laqueus Zone, ROM 38949 and 38950; all x 4.8. (Note: base of F is the continuation of
the top of Cc.)
B,G. Monograptus triangulatus fimbriatus (Nicholson), Peel River, collection at
488 m, magnus Zone?, ROM 38951 and 38815; x 5.9, x 5.5.
D. Monograptus cf. triangulatus (Harkness), Peel River, collection at 487.4 m,
triangulatus Zone, ROM 38952; x 3.4.
E. Monograptus cf. triangulatus separatus Sudbury, Peel River, collection at
480.4 m, triangulatus Zone, ROM 38818; x 4.0.
108
Material
Several or more moderately well-preserved specimens from each collection.
Illustrated specimens are ROM 38806 to 38807 and 38947 to 38948.
Description
The rhabdosome is more or less straight throughout its length, except for the region of
the proximal two thecae which is weakly dorsally curved. The sicula is 1.4 to 1.5 mm
long and its apex is level with the tip of theca 1. Stipe width ranges from 0.5 to
0.7 mm across theca | to a maximum of about 1.6 mm, although one specimen
attains a width of 2.0 mm.
Proximal thecae are rather strongly, simply hooked and the apertural regions may
be pointed or bear a spine; the hooked portion occupies about one-half of the stipe
width and thecae number 10 to 11 in 10 mm proximally. Distal thecae overlap
one-third to one-quarter, occupy one-half to two-thirds of the stipe width, and number
8 to 9 in 10 mm; they are very strongly hooked to lobate in cross-section, probably
due to retroversion, and may or may not bear spines.
Discussion
The study specimens differ from those described by Elles and Wood (1913) in thecal
spacing, but are similar in sicular length. A comparable sicular length of 1.5 mm was
reported in specimens from the Kolyma region (Obut et al., 1967). On the other hand,
the Yukon material differs considerably in this respect from that of Rickards (1970)
and Hutt (1975), who quote a sicular length of only 1.0 mm. Sicular length may
increase up the stratigraphic column, a possibility alluded to by Hutt (1975: 106).
Monograptus sidjachenkoi (Obut and Sobolevskaya, 1965)
Figs. SN; P;sR; 27B; E, F
Pernerograptus sidjachenkoi Obut and Sobolevskaya, 1965: 61.
Pernerograptus sidjachenkoi, Obut and Sobolevskaya, 1967: 111.
?Paramonoclimacis typicalis Wang and Ma, 1977: 362.
?Paramonoclimacis similis Wang and Ma, 1977: 361.
Occurrence
Convolutus Zone, Peel River, at 496.2, 502.3, 507.8, and 512.8 m; and Blackstone
River, at 69.2 and 70.4 m.
109
Material
Three to ten, fragmentary, poorly to moderately preserved specimens in each
collection. Illustrated specimens are ROM 38796 to 38798 and 38937.
Description
The proximal portion of the rhabdosome is tightly to moderately tightly coiled
through an arc ranging from 270 degrees to 400 degrees, whereas the distal portion is
straight, or weakly dorsally curved. The proximal region is delicate and attenuated
and bears a sicula which appears to be about 0.9 mm long (though in some specimens
it may be as much as 1.4 mm long).Width of the rhabdosome increases rapidly from
0.5 to 0.6 mm across theca 1, to a maximum ranging from 1.0 to 1.5 mm distally.
The proximal thecae are lobed, with the lobes occupying one-quarter the stipe
width and the ventral walls parallel the stipe axis; they number 10 to 12 in 10 mm.
The thecal lobes disappear in the region immediately distal of the strongly curved
portion and the thecal apertures are only hooded excavations in which the hoods
occupy about one-fifth to one-seventh the stipe width. Distal thecae number 9 to 10 in
10 mm.
Discussion
The distinguishing characteristics of this species are the strongly curved proximal
region and the biform thecae similar to those of M. revolutus. The sicular end of the
Yukon specimens are generally poorly preserved, making the determination of the
sicular length difficult. In two instances, the sicula is clearly seen to be only 0.9 mm
in length. Obut and Sobolevskaya (1967) quote a sicular length of only 0.5 mm in
their material.
Paramonoclimacis typicalis and P. similis, described by Wang and Ma (1977),
appear to be identical to M. sidjachenkoi.
Monograptus speciosus Tullberg, 1883
Pigs, 9K; 30A7C) FE
Monograptus speciosus Tullberg, 1883: 21.
Monograptus (Streptograptus)speciosus, Boucek and Pribyl, 1942: 7.
Monograptus speciosus, Bjerreskov, 1975: 76.
Occurrence
Sakmaricus-laqueus Zone, Tetlit Creek, at 215 and 217 m, and tentatively at 216 and
220 m; tentatively from the spiralis Zone, Mount Sekwi, at 516.9 m; and Rock
River, at 245 m.
110
Material
Two to several mostly fairly to moderately preserved specimens from each collection;
those from Tetlit Creek at 217 m are very well preserved in partial relief in black
shale. Illustrated specimens are ROM 38813 and 38949 to 38950.
Description
The proximal end of this species has not been recovered, although one specimen from
Tetlit Creek, 217 m, may exhibit a bipolar structure such as illustrated in Bjerreskov
(1975: 77). The rhabdosome is broadly ventrally curved throughout its length and
stipe width ranges from a minimum of 0.5 mm proximally to an observed maximum
of 0.8 mm distally.
The prothecae are axially elongate and generally parallel to the stipe axis, whereas
the short metathecae are strongly hooked, so that the apertures point in a
dorsoproximal direction and occupy about one-quarter to one-third the stipe width.
There is some suggestion of mild torsion of the thecal hoods. Interthecal septa are
S-shaped and thecae overlap no more than one-third to one-half distally. Thecae
number 9 to 10 in 10 mm throughout the length of the rhabdosome.
Discussion
Bjerreskov (1975) noted that the thecae of this species are hooked and not lobate as
suggested by Boucek and Pribyl (1942). Slight thecal torsion, followed by
compression, could, however, lead to lobelike thecal profiles.
Monograptus spiralis (Geinitz, 1852)
Pigs 9P-32A-6.
Graptolithus spiralis Geinitz, 1852: 700.
Spirograptus spiralis, Pribyl, 1944: 6.
Oktavites spiralis, Obut and Sobolevskaya, 1968: 82.
Monograptus (Spirograptus) spiralis spiralis, Schauer, 1971: 76.
Monograptus spiralis spiralis, Bjerreskov, 1975: 72.
For additional references, see Pribyl, 1944, and Bjerreskov, 1975.
Occurrence
Rare in the turriculatus Zone, common and abundant in the spiralis Zone, and
uncommon in the lower part of the sakmaricus-laqueus Zone. It is not as ubiquitous
as M. priodon, but is common to abundant everywhere in the spiralis Zone. Collected
from Whittaker Range, at 728.5. 774.2, 795.5, 815.9, 823, 827.5, 836.7, 839.7,
855.6, and 922 m; Peel River, at 579.7, 611.4, 612.6, 614.2, 615.7, 629.4, and
630.9 m; Tetlit Creek, at 168, 182, 185, 213, and 217 m; Rock River, at 315, 323,
111
326, and 345 m; Blackstone River, at 103.8 m; Clearwater Creek, at 70.1, 73.2,
76.2, 77.7, 79.2, 85.3, 86.9, and 88.4 m; and Mount Sekwi, at 516.9 m.
Material
Specimens common to abundant, poorly to well-preserved in collections. Illustrated
specimens are ROM 38819 and 38954 to 38956.
Discussion
M. spiralis is readily distinguishable from most other monograptids by its
multispiralled rhabdosome, which may coil through four or more volutions, and by its
possession of ‘‘isolate triangular and hooked thecae’’ (Bjerreskov, 1975: 72), the
hooked portions of which occupy a large proportion of the stipe width distally and
bear spinelike lateral projections throughout the rhabdosome. Uncompressed
specimens from Cape Phillips Formation clearly show the torsion of the thecal
apertures and the strong development of lateral, spinelike processes. Upon
compression, one of the processes is typically hidden from view.
The rhabdosome of this species attains a distal width of at least 3.0 mm and thecae
number 12 in 10 mm proximally and 8 to 9 in 10 mm distally.
Monograptus spiralis cf. contortus Perner, 1897
(not illustrated)
cf. Monograptus plana var. contorta Perner, 1897: 26.
cf. Spirograptus spiralis contortus, Pribyl, 1944: 193.
?Monograptus spiralis aff. contortus, Hutt, 1975: 107.
Occurrence
Sedgwicki and turriculatus zones, and lower spiralis Zone. Collected from Peel River,
at 570.9 and 582.2 m; Rock River, at 306 and 309 m; and Blackstone River, at
TT 2 a
Material
Specimens fairly to moderately preserved, common in Peel River, 570.9 m
collection, and rare to uncommon in each of the other collections.
Discussion
This subspecies possesses the spiral structure, the thecal outline, including spinelike
2
Fig. 31 A-c. Monograptus tullbergi spiraloides (Pribyl), Rock River, collection 5F, spiralis Zone,
ROM 38953, 38821, and 38820; all x 2.9.
113
Fig. 32 A-c,F. Monograptus spiralis (Geinitz), spiralis Zone
A. Rock River, collection 6F, ROM 38954; x 2.2.
B. Mount Sekwi, collection at 516.9 m, ROM 38955; x 3.4.
C. Peel River, collection at 611.4 m, ROM 38819; x 3.4.
F. Rock River, collection SF, ROM 38956; x 4.1.
D,E,G. Monograptus turriculatus (Barrande), turriculatus Zone
D. Peel River, collection at 518.8 m, ROM 38957; x 4.0.
E. Blackstone River, collection at 92.7 m, ROM 38958; x 2.9.
G. Rock River, collection at 287 m, ROM 38959; x 4.3.
114
lateral projections, and the thecal spacing of M. spiralis spiralis. It typically differs,
however, in having a distal width of no more than 2.0 to 2.2 mm, inclusive of the
spinelike projections, a sicular length of 1.4 to 1.5 mm and, most conspicuously, a
more delicate proximal end which may be straight, more weakly dorsally curved than
the rest of the rhabdosome, or even gently ventrally curved. Regardless of the
direction of curvature of the proximal portion, it is, because of its relative
straightness, typically overlapped by more distal portions of the first whorl.
The stipe width of the study specimens is about 1.5 mm, and therefore less than
typical of M. spiralis contortus. In other respects it is very similar.
Monograptus cf. tenuissmus (Obut and Sobolevskaya, 1968)
Figs. 80, Q; 27D
cf. Globosograptus tenuissmus Obut and Sobolevskaya, 1968: 101.
Occurrence
Sedgwicki Zone, Peel River, at 515.1 and 519.4 m; tentatively from the triangulatus
and magnus? zones, Peel River, at 481.9 and 482.5 m.
Material
Specimens moderately well preserved, small, mostly with proximal ends. Collections
comprise six specimens from Peel River, 519.4 m, 10 specimens from 515.1 m, a
single specimen from each of the other two collections. Illustrated specimens are ROM
38799 to 38800 and 38940.
Description
The rhabdosome is moderately dorsally curved proximally and weakly so distally.
Width ranges from 0.4 to 0.6 mm across theca 1 to a maximum of 0.7 to 0.8 mm
distally. The sicula is narrow, very weakly ventrally curved, 1.0 mm long, and its
apex is level with theca 1.
The thecae are scarcely in contact. The prothecae are inclined 30 to 40 degrees to
the stipe axis. The metathecae are large, enrolled, lobate, and in all likelihood
introverted; they comprise more than one-half the total thecal length. Thecae number
9 to 10 in 10 mm proximally and 8 to 10 in 10 mm distally.
Discussion
The specimens from Yukon resemble M. tenuissmus of Obut and Sobolevskaya
(1968) closely in overall rhabdosomal shape, thecal profile, and thecal spacing. They
differ in possessing a sicula which is 1.0 mm, rather than 0.5 mm, long.
The study material differs from M. inconspicuous Bouéek (see Boucek and Pribyl,
1951) in possessing considerably more widely spaced thecae. It differs from M.
wimani Boucek in possessing much more closely spaced thecae and more steeply
inclined prothecae.
Monograptus triangulatus fimbriatus (Nicholson, 1868)
Figse: 9°2M40;-30B8,G
Graptolites fimbriatus Nicholson, 1868: 536.
Monograptus separatus fimbriatus, Sudbury, 1958: 499.
Demirastrites pectinatus pectinatus, Obut and Sobolevskaya 1968: 108.
Monograptus triangulatus fimbriatus, Rickards, 1970: 82.
Monograptus triangulatus fimbriatus , Hutt, 1975: 110.
Occurrence
Triangulatus Zone and possibly magnus? Zone, Peel River, at 488 and 490.7 m, and
tentatively 489.2 m.
Material
Rare in either collection, and only moderate preservation of short, proximal portions
of the rhabdosome. Illustrated specimens are ROM 38814 to 38816 and 38951.
Discussion
This is the only subspecies of the triangulate monograptids with triangular thecae
throughout the length of the rhabdosome. The rhabdosome is distinctly hook-shaped
and the width increases rapidly from about 0.6 mm proximally to a maximum of
1.3 mm or more within the distance of the first 8 to 10 thecae. The thecae are spaced
at the rate of 12 to 11 or 10 in 10 mm. The sicula is 0.9 to 1.0 mm long. This species
may be conspecific with M. pectinatus Richter, which it closely resembles in the lack
of nonrastritiform proximal thecae.
Monograptus cf. triangulatus separatus Sudbury, 1958
Figs. 90; 30E
cf. Monograptus separatus separatus Sudbury, 1958: 496.
Occurrence
Triangulatus Zone, Peel River, at 480.4 m.
116
Material
A single, well-preserved, incomplete specimen lacking the sicular end. The illustrated
specimen is ROM 38818.
Discussion
The single specimen of this species, although clearly a member of the triangulate
monograptid group, differs from M. triangulatus fimbriatus in possessing four to five
isolated, rastritiform proximal thecae; conversely, it differs from M. ¢. triangulatus in
possessing fewer rastritiform proximal thecae and in that the distal thecae are more
robust. The thecae number 12 in 10 mm proximally and 8 in 10 mm distally, a
spacing less than that described by Hutt (1975), while the rhabdosome attains a
maximum width of 1.6 mm.
Monograptus tullbergi spiraloides (Pribyl, 1944)
Riess LOA, Be 3 VA-C
Spirograptus tullbergi spiraloides Pribyl, 1944: 203.
Spirograptus tullbergi spiraloides, Munch, 1952: 116.
Monograptus (Spirograptus) tullbergi spiraloides, Schauer, 1971: 76.
Occurrence
Turriculatus and spiralis zones. Collected from Peel River, at 553.8 m; Rock River
collections 5F, 7F, 10F; and Delorme Range, at 777.2 m.
Material
Very abundant and well preserved in collections from Rock River, and rare and
fragmental from the other localities. Illustrated specimens are ROM 38820 to 38821
and 38953.
Description
The rhabdosome is loosely coiled through two, or occasionally three, volutions.
Typically, the thecae are on the convex side of the stipe, but, owing to periodic stipe
torsion, thecae may occasionally lie on the concave side for a short distance. The
proximal portion, encompassing the first 8 to 10 thecae, ranges from straight to gently
ventrally or dorsally curved, so that the proximal region is overlapped by the first, or
even second, volution. The sicula is 1.2 to 1.3 mm long and its apex is level with the
tip of theca 1. Stipe width increases gradually from about 0.5 mm across theca 1, toa
maximum of 1.5 to 2.0 mm distally.
117
The thecae are triangular in cross-section, and proximal thecae are exactly like
those of M. tullbergi and M. falx. Distal thecae overlap by about one-third, but
maintain the same profile as proximal thecae. The thecal apertures are clearly
asymmetric and underwent torsion. Upon compression, the apertural profiles are
beaklike when compressed, but are without any kind of spines or lateral processes.
Thecae number 10 to 11 in 10 mm proximally and 8 to 9 in 10 mm distally.
Discussion
The large size of the rhabdosome and overlapping nature of the proximal portions of
the rhabdosome of the Yukon specimens make them very like M. spiralis contortus.
They differ, however, in the presence of M. tullbergi-type thecal profiles, and
significantly in the total lack of apertural ‘‘spines’’ and a weak and gently widening
portion to the rhabdosome. On the other hand, the study specimens differ from typical
M. tullbergi spiraloides in their large size.
Monograptus turriculatus (Barrande, 1850)
Figs. 9N32D,ENG, 33A-€
Graptolithus turriculatus Barrande, 1850: 56.
Monograptus turriculatus, Elles and Wood, 1913: 438.
Monograptus turriculatus mut. minor Boucek, 1932: 155.
Monograptus (Spirogr.) turriculatus turriculatus, Schauer, 1971: 74.
Monograptus turriculatus minor, Schauer, 1971: 74.
Monograptus turriculatus, Bjerreskov, 1975: 70.
Monograptus turriculatus , Hutt, 1975: 111.
Occurrence
Turriculatus Zone. Collected from Peel River, at 516.9, 517.9, 518.8, 523, 526,
528.8, 531.9, 536.1, 544.4, 548.9, 559.3 m; Tetlit Creek, at 144 m; Rock River, at
282, 287, 293, and 302 m; Mount Sekwi, at 547.4 and 527.6 m; Blackstone River, at
80.2, 83.8, 85.3, 86.9, 88.7, 89, 91.4, 92.7, 94.8, and 99 m; Delorme Range, at
774.2 and 777.2 m; and Clearwater Creek, at 67.1, 68.6, and 70.1 m.
Material
This species, next to M. priodon and M. spiralis, is one of the most abundant and
ubiquitous of all monograptids. Specimens moderately well to well preserved on
black shale, common to abundant in most collections. Illustrated specimens are ROM
38817 and 38957 to 38962.
118
em
Nd
a
y
D,E.
Monograptus turriculatus (Barrande), Peel River, turriculatus Zone
A. Collection at 548.9 m, ROM 38960; x 2.2.
B. Collection at 559.3 m, ROM 38961; x 3.5.
Cc. Collection at 526 m, ROM 38962; x 3.8.
Monograptus cf. undulatus Elles and Wood, Blackstone River, collection at 7
sedgwicki Zone, ROM 38963 and 38964; x 1.7, X 3.6.
otis)
pay
m,
119
Fig. 34 A,B,D,F,G. Rastrites approximatus Perner
A. Blackstone River, collection at 65.5 m, argenteus Zone?, ROM 38965; xX 1.8.
B,F,G. Peel River, collection at 480 m, triangulatus Zone, ROM 38824, 38966, and
3S96TE DG 5535 SS Spex Eo
D. Peel River, collection at 480.4 m, triangulatus Zone, ROM 38823; Xx 4.8.
C,E,H. Rastrites approximatus geinitzi Tornquist, sedgwicki Zone
C,E. Blackstone River, collection at 72.2 m, ROM 38968 and 38969; x 3.8, x 3.5.
H. Peel River, collection at 515.1 m, ROM 38970; x 3.6.
120
Description
The rhabdosome is small to large, coiled in a conical spiral through as many as seven
whorls. The stipe widens slowly and continuously from about 0.5 to 0.6 mm
proximally to nearly 3 mm in distal regions of large specimens. The sicula is 1.1 to
1.2 mm long.
The thecae are triangular in cross-section, with small apertural hooks, and possess
rather long and sometimes bifurcating apertural spines. The thecae number as many
as 14 to 16 in 10 mm proximally, and about 12 in 10 mm distally.
Discussion
The apertural and spine structures of this species are complex and are not fully
understood. As noted by Hutt (1975) and Bjerreskov (1975) there may be no
justification for the recognition of the subspecies, minor. The great range in variation
in size of the Yukon material and the presence of both ‘‘subspecies’’ in the same
collections adds support to the idea of a growth series. M. turriculatus is very
commonly associated with M. exiguus primulus.
Monograptus cf. undulatus Elles and Wood, 1913
Fig. 33D, E
cf. Monograptus undulatus Elles and Wood, 1913: 432.
Occurrence
Sedgwicki Zone, Blackstone River, at 72.2 m.
Material
Abundant, tangled distal fragments, moderately preserved, on black shale bedding
plane. Illustrated specimens are ROM 38963 to 38964.
Discussion
The presence of only distal fragments of the rhabdosome precludes positive
identification. The stipe attains a maximum width of 1.0 mm and the thecae number
seven or eight in 10 mm. The thecae are triangular in profile, occupy about one-half
the stipe width and overlap only slightly; they are inclined about 20 degrees to the
axis of the stipe and the metathecae form moderately tight hooks. The apertures
appear to face in a slightly dorsoproximal direction, probably owing to a slight
retroversion.
12]
The thecae of the study specimens resemble those illustrated by Elles and Wood
(1913: 432, fig. 295) much more closely than those of Hutt (1975: text fig. 19, fig.
6).
Genus Rastrites Barrande, 1850
Type Species
Rastrites peregrinus Barrande, 1850, from the Llandovery of Bohemia; subsequent
designation Hopkinson, 1869.
Rastrites approximatus Perner, 1897
Figs 10C; 1,5;°34A4, B.D) FYG
Rastrites peregrinus var. approximatus Perner, 1897: 15.
Rastrites approximatus approximatus, Pribyl, 1941: 7.
Monograptus (Rastrites) approximatus, Waterlot, 1945: 90.
Rastrites approximatus approximatus, Schauer, 1967: 177.
Occurrence
Triangulatus and argenteus zones. Collected from Peel River, at 480, 480.4, and
tentatively 481.9 m; Blackstone River, at 65.5 m; and Tetlit Creek, at 138 m and
tentatively 139 m. Additionally several specimens from the sedgwicki Zone of
Blackstone River, at 72.2 m, and Peel River, at 515.1 m, are tentatively referred to
this species.
Material
Specimens incomplete, poorly to moderately well preserved, comprising 12
specimens from Blackstone River, at 65.5 m, and only a few specimens from each of
the other collections. Illustrated specimens are ROM 38822 to 38824 and 38965 to
38967.
Description
The rhabdosome is hook-shaped, with the proximal region being typically tightly
coiled through nearly 360 degrees and the distal portions gently dorsally curved. The
sicula is narrow and appears to be less than 1.0 mm long. The thecae are
approximately at right angles to the stipe axis, 0.5 to 0.8 mm long across theca 1, and
attain a maximum length of 2.2 to 2.6 mm distally. They are fairly stout, more or less
parallel sided, 0.4 to 0.5 mm wide distally and tend to be pointed at their distal ends,
and number 16 to 12 in 10 mm.
£22
Discussion
The thecal spacing and the possession of stout thecae are typical of this species. The
Yukon specimens occur in beds older than is typical of the European occurrences,
where the species appears to be confined to the convolutus Zone (P¥ibyl, 1941;
Schauer, 1967).
Rastrites approximatus geinitzi Tornquist, 1907
Fig. 34C, E, H
Rastrites approximatus var. Geinitzi Tornquist, 1907: 9.
?Monograptus (Rastrites) approximatus var. Geinitzi, Elles and Wood, 1914: 492.
Monograptus (Rastrites) approximatus var. Geinitzi, Waterlot, 1945: 89.
Rastrites approximatus geinitzi, Schauer, 1967: 177.
Occurrence
Convolutus and sedgwicki zones, Peel River, at 507.8 and 515.1 m; sedgwicki Zone,
Blackstone River, at 72.2 m.
Material
Several incomplete, moderately well-preserved specimens from each collection.
Illustrated specimens are ROM 38968 to 38970.
Description
The rhabdosome is broadly dorsally curved, more so proximally, through 90 degrees
or more. The sicula is not seen. Thecal length ranges from about 0.9 to 1.0 mm
across theca 1, to a maximum of 3.2 to 3.5 mm distally. The thecae are perpendicular
to the axis of the stipe and very narrow and delicate in appearance; they widen
towards their apertural ends, where the tip is two-pronged, and number 10 to 11 in
10 mm proximally and 9 to 12 in 10 mm distally.
Discussion
This subspecies differs from the typical form in possessing fewer thecae in 10 mm,
longer and more delicate thecae with split apertural ends, and a much less strongly
coiled rhabdosome. It differs from R. longispinus and R. perfectus in possessing
anteriorly widening, distally notched thecae.
123
Rastrites distans Lapworth, 1876
not illustrated
Rastrites distans Lapworth, 1876: 313.
Rastrites distans abbreviatus Tornquist, 1907: 12 (pars.)
Monograptus (Rastrites) equidistans, Waterlot, 1945: 89.
Rastrites distans, Schauer, 1967: 183.
Occurrence
Sedgwicki Zone, Peel River, at 513.6 m.
Material
Three fragmentary, poorly preserved specimens lacking proximal ends.
Description
The rhabdosomal fragments are straight and very delicate, with thecae perpendicular
to the stipe axis. The thecae are very thin, appear to be hooked at their extreme distal
ends, are spaced at the rate of three to four in 10 mm, and are 3.0 to 3.7 mm long. The
chief characteristic of the species is that the thecal length and spacing are nearly
identical.
Rastrites cf. distans Lapworth, 1876
Figs. 10E; 35A
cf. Rastrites distans Lapworth, 1876: 313.
Occurrence
Sedgwicki Zone, Peel River, at 515.1 m.
Material
Several incomplete, moderately well-preserved specimens. Illustrated specimens are
ROM 38828 and 38971.
Description
The rhabdosome is gently curved proximally, nearly straight distaily. The sicula is 0.9
124
Fig. 35 A.
B,D.
GEG;
Se UA
Rastrites cf. distans Lapworth (and R. rostratus sp. nov.), Peel River, collection at
515.1 m, sedgwicki Zone, ROM 38971; x 5.1.
Rastrites linnaei Barrande
B. Peel River, collection at 528.8 m, turriculatus Zone, ROM 38972; x 3.2.
D. Blackstone River, collection at 74.7 m, sedgwicki Zone, ROM 38973; X 3.8.
Rastrites cf. hybridus Lapworth
CE. Peel River, collection at 515.1 m, sedgwicki Zone, ROM 38974 and 38975;
both x 4.7.
G. Blackstone River, collection at 66.4 m, convolutus Zone, ROM 38976; X 2.6.
Rastrites rostratus sp. nov., Peel River, sedgwicki Zone
F. Collection at 519.4 m, ROM 38977; x 7.0.
HJ,K. Collection at 515.1 m, ROM 38843, 38978, and 38842; x 6.0, x 5.1, X 4.2.
Rastrites cf. linnaei Barrande, Peel River
1. Collection at 513.6 m, sedgwicki Zone, ROM 38979; x 7.6. 125
L. Collection at 531.9 m, turriculatus Zone, ROM 38980; x 3.2.
Fig. 36 A.B. Rastrites cf. perfectus Pribyl, Peel River, collection at 519.4 m, sedgwicki Zone, ROM
38837 and 38838; x 3.0; x 3.3.
C,E,G. Rastrites maximus Carruthers, Peel River
c. Collection at 513.6 m, sedgwicki Zone, ROM 38981; x 3.0.
E.G. Collection at 521.8 m, turriculatus Zone, ROM 38833 and 38832; x 4.2.
DF. Rastrites longispinus Perner, Peel River
D. Collection at 507.8 m, convolutus Zone, ROM 38831; x 4.6.
F. Collection at 477 m, triangulatus Zone, ROM 38830; x 5.2.
126
to 1.0 mm long and very narrow. Theca 1 is 0.9 to 1.0 mm long and thecal length
increases rapidly so that, by theca 5, the maximum length of 2.0 to 2.2 mm is
attained. The thecae are inclined 60 degrees to 90 degrees to the stipe, are thin and
delicate, weakly hooked at their distal ends; there are 8 to 9 in 10 mm proximally and
6.0 to 6.5 in 10 mm distally.
Discussion
This species differs from the typical R. distans in possessing more closely spaced
thecae. In other aspects it is similar. From species such as R. longispinus and R.
perfectus it differs in possessing shorter and considerably more widely spaced thecae.
Rastrites cf. hybridus Lapworth, 1876
Eig. S5CKE, G
cf. Rastrites peregrinus var. hybridus Lapworth, 1876: 313.
Occurrence
Convolutus and sedgwicki zones, Peel River, at 496.2, 513.6, and 515.1 m;
Blackstone River, at 66.4 m.
Material
Specimens incomplete, poorly to moderately preserved, comprising more than 20
specimens from the 513.6 m collection on Peel River, and several from each of the
other two collections. [llustrated specimens are ROM 38974 to 38976.
Description
The rhabdosome is fairly strongly dorsally curved proximally, and weakly curved
distally. The width of the rhabdosome is 0.6 to 0.9 mm measured across theca |, and
increases to a maximum of 2.1 to 2.3 mm distally. The sicula appears to be about
1.0 mm long.
The thecae are more or less perpendicular to the axis of the stipe, especially
distally, and are 0.25 to 0.3 mm wide at their widest portion and slightly narrower at
their bases. Their distal ends are slightly hooked, or manifest a hook or pronglike
development (the *‘two terminal threadlike processes’’ of Elles and Wood, 1913:
491). Thecae number 12 to 14 in 10 mm proximally and about 10 in 10 mm distally.
Discussion
The chief difference between the typical R. hybridus and the Canadian specimens is
127
in the slightly closer spacing of thecae. In all other parameters, including pronglike
distal processes of the thecae, they are identical.
Rastrites linnaei Barrande, 1850
Fig. 35B, D
Rastrites linnaei Barrande, 1850: 65.
Rastrites linnaei, Tornquist, 1907: 14.
Monograptus (Rastrites) linnaei, Elles and Wood, 1914: 493.
Rastrites linnaei, Pribyl, 1941: 10.
Rastrites linnaei, Schauer, 1967: 180.
Occurrence
Sedgwicki and turriculatus zones, Peel River, at 513.6, 528.8, and 531.9 m;
Blackstone River, at 74.7 m.
Material
About ten fragmentary, poorly preserved specimens without proximal ends from the
four occurrences. Illustrated specimens are ROM 38972 to 38973.
Description
The proximal end of rhabdosome is unknown. Distally, the rhabdosome is
approximately straight or weakly curved. Thecal inclination ranges from 70 to 90
degrees. Thecae are long, essentially parallel sided, and about 0.4 mm wide; they are
slightly hooked at their distal ends and attain a maximum observed length of 6 to
7 mm. The thecae are spaced at the rate of three to seven in 10 mm, mostly four to six
in 10 mm.
Rastrites longispinus Perner, 1897
Figs. 10F-H; 36D, F
Rastrites peregrinus var. longispinus Perner, 1897: 9.
Monograptus (Rastrites) longispinus, Elles and Wood, 1914: 489.
Rastrites longispinus , Pribyl, 1941: 6.
Rastrites longispinus, Schauer, 1967: 176.
Rastrites longispinus, Bjerreskov, 1975: 82.
Occurrence
Triangulatus and convolutus zones, and possibly the argenteus Zone, Peel River,at
128
477 and 507.8 m; and Tetlit Creek, at 139m. A poorly preserved specimen is
tentatively identifed from the convolutus Zone of Tetlit Creek, at 142 m.
Material
Specimens fairly to moderately well preserved, comprising five from Peel River at
477 m and three from 507.8 m, including proximal ends, and a single distal fragment
from Tetlit Creek, at 139 m. Illustrated specimens are ROM 38829 to 38831.
Description
The rhabdosome is moderately strongly dorsally curved proximally and weakly so, or
even Straight, distally. Width is 0.8 mm measured at the first theca and increases
fairly rapidly to a maximum of 3.4 to 3.6 mm distally (possibly as much as 4.0 mm).
The sicula is unknown.
The thecae are perpendicular to the stipe axis, are relatively thin and delicate in
appearance (0.2 to 0.25 mm wide), parallel-sided, and expand in width only very
slightly at their apertural ends. The thecae number 13 in 10 mm proximally and 9 to
11 in 10 mm distally (in one instance there may be as few as 7 in 10 mm distally).
Discussion
The species bears a strong resemblance to the younger R. perfectus, from which it is
distinguished by its more closely spaced thecae.
Rastrites maximus Carruthers, 1867
Figs. 11A, B; 36C, E, G
Rastrites maximus Carruthers, 1867: 541.
Rastrites maximus, Tornquist, 1907: 15.
Monograptus (Rastrites) maximus, Elles and Wood, 1913: 494.
Rastrites maximus, Schauer, 1967: 184.
Rastrites maximus, Bjerreskov, 1975: 84.
Occurrence
Sedgwicki and turriculatus zones, Peel River, at 513.6, 516.3, and 521.8 m;
tentatively from Blackstone River, at 72.2 m.
Material
Several distal fragments in each collection, all fairly to moderately well preserved on
black shale. Illustrated specimens are ROM 38832 to 38833 and 38981.
129
Description
The rhabdosome is incomplete. The virgular region is very thin and delicate. The
bases of the thecae are triangular; the thecae then become thinner and essentially
parallel sided and about 0.25 mm wide. The width increases towards the apertural
region, resulting in a distinct clublike hook possessing an apparent apertural spine.
The thecae range in length from 5.5 to 10 mm and are spaced at the rate of 2.5 to 3.5
in 10 mm.
Discussion
The specimens from the Yukon differ from the typical R. maximus in possessing
shorter thecae; they are, however, all short fragments and therefore give no indication
of the maximum thecal length. Thecal shape and spacing are typical of R. maximus
(Bjerreskov, 1975: 84, fig. 24).
Rastrites orbitus Churkin and Carter, 1970
Figs icmp a3s Er es) Se
Rastrites orbitus Churkin and Carter, 1970: 45.
Occurrence
Magnus?, argenteus, and convolutus zones, Peel River, at 490.7, 491.4, 508.4, and
512.8 m; Blackstone River, at 69.2 and 70.4 m; and Tetlit Creek, at 142 m.
Material
Several, or more, incomplete, poorly to moderately well-preserved specimens from
each collection, none with the sicular end. Illustrated specimens are ROM 38834 to
38835 and 38985 to 38986, and tentatively 38836.
Description
The rhabdosome is circular, or nearly so, in outline, with a more or less uniform
curvature through an arc greater than 360 degrees. Proximal width appears to be
about 0.6 mm measured through theca 1 and maximum distal width, inclusive of the
virgula, is 1.8 mm, although the majority of specimens are in the range 1.3 to
1.4 mm.
The thecae are generally inclined about 70 degrees to the virgula. They are
relatively broad (0.3 to 0.35 mm) and generally increase in width towards their
apertural ends, which are sharply curved into a distinct hook. Thecae number 12 in
10 mm proximally and 8 to 10 in 10 mm distally.
130
D,G-J.
Rastrites phleoides Tornquist, Peel River, collection at 507.8 m, convolutus Zone,
ROM 38839 and 38840; both x 4.1.
Rastrites cf. orbitus Churkin and Carter, Peel River, collection at 508.4 m, convolutus
Zone, ROM 38836: x 3.5.
?Diversograptus ramosus Manck
DI. Peel River, collection at 528.5 m, turriculatus Zone, ROM 38982 and 38983;
bi Eat i, a Jel
GJ. Rock River, collection 9F, spiralis Zone, ROM 38708 and 38984, x 4.8, x 4.0.
H
Peel River, collection at 630.9 m, spiralis Zone, ROM 41647, x 3.6.
Rastrites orbitus Churkin and Carter, Peel River
E. Collection at 512.8 m, convolutus Zone, ROM 38985; Xx 3.8.
F. Collection at 490.7 m, argenteus Zone, ROM 38986; x 3.4.
Discussion
The nearly circular rhabdosome is distinctive of this species and this feature
distinguishes it from species with similar thecae, such as R. peregrinus and R.
richteri. In Alaska, this species is found only in the “‘gregarius Zone’’ of Churkin
and Carter (1970), a zone that is equivalent to the triangulatus, magnus?, and
argenteus zones of the present study.
Rastrites cf. perfectus Pribyl, 1942
Figs. 11F, H; 36A, B
cf. Rastrites perfectus Pribyl, 1942: 3.
Occurrence
Sedgwicki Zone, Peel River, at 515.1 and 519.4 m; and Blackstone River, at 77.2 m.
Material
About five poorly to moderately well-preserved specimens of mostly distal portions
of the rhabdosome from each collection. Illustrated specimens are ROM 38837 to
38838.
Description
The rhabdosome appears to be large, probably in excess of 30 mm in length. The
proximal end is apparently gently to moderately dorsally curved, while the distal
region is straight. The sicula is 0.9 to 1.0 mm long. Stipe width ranges from 0.9 to
1.0 mm across theca 1 to 3.0 to 4.2 mm distally.
The thecae may or may not be perpendicular to the stipe axis, are delicate in
appearance, 0.2 to 0.25 mm wide, and are spaced 9 to 11 in 10 mm proximally and 7
to 9 in 10 mm distally. The distal ends of the thecae are expanded and exhibit
double-pronged processes.
Discussion
Thecal spacing and length of the study specimens are very similar to the typical R.
perfectus. Since, however, most of the material is fragmental and mostly of distal
parts of the rhabdosome, only a tentative identification is possible.
132
Rastrites phleoides Tornquist, 1887
Figs. 11G,J, M; 37A, B
Rastrites phleoides Tornquist, 1887: 490.
Rastrites phleoides, Tornquist, 1907: 11.
Rastrites phleoides, Pribyl, 1941: 16.
Demirastrites phleoides, Munch, 1952: 130.
Rastrites phleoides, Hutt, 1975: 115.
Occurrence
Argenteus? and convolutus zones, Peel River, at 491.4, 495.9, 508.4, and 512.8 m;
and tentatively Tetlit Creek, at 142 m.
Material
Specimens rare to uncommon in any collection, poorly to moderately well preserved.
Illustrated specimens are ROM 38839 to 38841.
Description
The rhabdosome is spiralled through at least two complete volutions in spite of the
fact that the proximal end is not present in any specimen. The thecae are somewhat
undulose in width; the proximalmost thecae seen are delicate and only about 0.2 to
0.25 mm wide, whereas the distal thecae are more robust and 0.3 to 0.35 mm wide.
Thecal apertures are flared outward and split by a V-shaped notch and bear two thin,
hairlike spines (‘‘bristles’’ of Tornquist, 1907: 11). The longest thecae observed
measure 3.4 mm and thecal spacing is at the rate of 10 to 12 in 10 mm.
Discussion
The presence of well-developed, twin terminal spines on each theca is characteristic
of this species, resembling only the proximal region of M. convolutus. R. phleoides is
readily distinguished from M. convolutus, however, by the fact that spine-bearing
thecae are present throughout the entire length of its rhabdosome.
Rastrites rostratus sp. nov.
Figs. 111, K, L; 35F, H, J, K
Occurrence
From the sedgwicki Zone of Peel River, 515.1 and 519.4 m.
Material
Ten moderately well-preserved specimens from 515.1 m and two from 519.4 m, all
apparently juvenile stages. Described specimens consist of ROM 38843 (holotype) and
38842, 38844, 38977, and 38978 (paratypes).
Etymology
From rostratus, Latin for beaked.
Diagnosis
Rhabdosome hook shaped, thecae broad at the bases and nearly in contact, narrowing
toward distal end and abruptly expanding into prominent clublike hooks bearing a
single beaklike process. Thecae 14 to 16 in 10 mm.
Description
The rhabdosome is hook shaped, moderately strongly curved proximally, much less
so distally. All rhabdosomes are small and probably immature. The proximal two or
three thecae are rastritiform and more or less parallel-sided. The remaining thecae are
broad-based and nearly in contact, narrow in their mid regions and then are abruptly
hooked over into very broad clublike structures which project in both a proximal and
distal direction. On the proximal side of the apertural region of the thecae, the thecal
apertures are protracted into a beaklike process. The net effect of the development of
the clublike apertural region is a profile resembling a bird’s head. Thecal length
increases rapidly; theca 1 is 0.5 to 0.7 mm, theca 3 about 0.9 mm, theca 4 is 1.4 mm
and theca 8 is 1.8 mm, the latter being the maximum observed length.
Discussion
This species of Rastrites resembles no other known species in the nature of its thecal
apertural processes. The bird-head structures of the apertural regions are probably
asymetrically developed laterally expanded hoods, which when crushed, take on the
present profile.
Genus Diversograptus Manck, 1923
Type Species
Diversograptus ramosus Manck, 1923, from the Silurian of Germany; original
designation.
134
?Diversograptus ramosus Manck, 1923
Bisse OSU, 37 DG)
?Diversograptus ramosus Manck, 1923: 283.
Occurrence
hurricuiamssand the: spiralis zones of Peel’ River; at 528:5;,531.9;615.7, and
630.9 m; Blackstone River, at 74.7 m; and Rock River, collections 9F, 10OF.
Tentatively identified from Peel River, at 602.6 m, and Blackstone River, at 74.7 and
86.9 m.
Material
Specimens incomplete, fairly to moderately preserved, common in Peel River
collection at 615.7 m, rare in other collections; only a very few show the bipolar
structure. Illustrated specimens are ROM 38708 to 38709 and 38982 to 38984.
Description
The rhabdosome is long and flexuous and width increases gradually from 0.45 to
0.5 mm proximally to 0.6 to 0.7 mm distally. The sicula is not visible; instead some
specimens show an apparent overlapping of opposite facing proximal thecae.
The prothecae are straight and inclined at an angle of about 10 degrees, whereas the
metathecae, which comprise about one-third the thecal length, are abruptly hooked
into fairly strong lobes which occupy about one-half to two-thirds the stipe width.
Thecae number 8 to 10 in 10 mm proximally and 8 to 9 in 10 mm distally.
Discussion
The study specimens are similar to the typical D. ramosus in the shape and spacing of
the thecae, but the critical thecal bulge (Rickards, 1973) was not recognized. The
Yukon specimens can, therefore, only be tentatively identified as the genus
Diversograptus.
Genus Barrandeograptus Bouéek, 1933
Type Species
Cyrtograptus pulchellus (Tullberg, 1883), from the Silurian of Sweden; subsequent
designation Bouéek, 1933.
135
Barrandeograptus aff. pulchellus (Tullberg, 1883)
Figs: 3R:-1/E2G
aff. Cyrtograptus pulchellus Tullberg, 1883: 36.
Occurrence
Sedgwicki Zone, Blackstone River, at 72.2 m.
Material
Three incomplete, moderately well-preserved fragments on black shale. Illustrated
specimens are ROM 38707 and 38887 to 38889.
Description
The proximal end of the rhabdosome is not seen, although one fragment is 35 mm
long. The stipes are gently curved and two orders of cladia are present. Stipe width is
0.9 mm and uniform throughout.
The thecae are triangular, inclined about 20 degrees and appear to overlap about
one-fifth their length and :umber 8 or 9 in 10 mm. The triangular portion of the
thecae comprises about nine-tenths their length, but clearly there is an abrupt torsion
of the metathecal portions of the thecae which conceals the apertures; the result is a
superficially simple, tubelike theca.
Cladia arise from apertural regions of the earlier formed branch, apparently
identical in nature to those of typical Cyrograptus (see Thorsteinsson, 1955; Lenz,
1974).
Discussion
Tullberg (1883) and Boucek (1933) stated that the thecae of B. pulchellus are simple
tubes (see also Bulman, 1970: V135). Bjerreskov (1975) showed that the simplicity is
illusory and that the metathecae undergo torsion.
The study specimens are similar in some of their characteristics to those of B.
pulchellus but apparently differ in possessing two orders of cladia. The lack of a
preserved proximal region allows only tentative identification. Additionally, the
Yukon specimens occur in much older beds than is typical of the species elsewhere
(lapworthi Zone of Bjerreskov, 1975).
136
Acknowledgements
I am grateful to the following individuals who at various times have provided
assistance and who have added materially to my graptolite collections: R.W.
Macqueen, A.E.H. Pedder, D.G. Perry, R. Ludvigsen, A.D. McCracken, J. Innis,
G. Klapper, and B.D.E. Chatterton. The acquisition of graptolites originally
collected by Chevron Stantard, Calgary, in the northern Cordillera during the late
1950s and early 1960s was essential to this study, and the loan of these graptolites
now under the care of S.J. Nelson, University of Calgary, is acknowledged. C.R.
Stelck, University of Alberta, kindly loaned me the Etherington collection from
Clearwater Creek, southern Northwest Territories. Appreciation is expressed to
B.Jones and L. van der Lee who kindly made other University of Alberta collections
available for study.
Finally warm appreciation is expressed to M. Bjerreskov, R.B. Rickards, and R.
Fortey, for the opportunities and assistance in examining the graptolite collections at
the University of Copenhagen, Cambridge University, and the British Museum
(Natural History), respectively. Financial support for this project has been
consistently provided through National Science and Engineering Research Council
grant A4236.
is?
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144
Appendix Index of Localities and Faunal Lists of Graptolites in Collections
The following generic abbreviations are used throughout the appendix: A—Atavograptus, Ak.—
Akidograptus, B.—Barrandeograptus, C.—Climacograptus, Ceph.—Cephalograptus, Cr.—
Coronograptus, Cy.—Cystograptus, Ct.—Cyrtograptus, D.—Diplograptus, Dm.—Dimorphograptus,
Div.—Diversograptus, G.—Glyptograptus, H.—Holoretiolites, L.—Lagarograptus, M.—Monograptus,
Mon.—Monoclimacis, O.—Orthograptus, Pc.—Pseudoclimacograptus, Pb.—Pribylograptus, P.—
Petalograptus, Pr.—Pristiograptus, Pl.—Plectograptus, Ps.—Pseudoplegmatograptus, Pt.—
Pseudoretiolites, R.-Rastrites, Ret.—Retiolites, Rh.—Rhaphidograptus, St.—Stomatograptus
LOCALITY 1 Rock River, main branch; approximately 66°55'N, 136°14’W. Note: Section not
measured, but graptolites collected in stratigraphic succession from oldest to youngest.
Collection 1F, spiralis Zone: M. spiralis, M. priodon, M. cf. geinitzi, M. parapriodon, Ret. geinitzianus
angustidens, St. sp.
Collection 2F, sakmaricus-laqueus Zone: Mon. cf. crenulatus, M. sp., Ct. aff. bohemicus, Ret.
geintzianus cf. angustidens
Collection 3F, sakmaricus-laqueus Zone: M. parapriodon, M. minimus, Ct. sakmaricus, C. aff.
bohemicus, Ret. geinitzianus angustidens
Collection 4F, sakmaricus-laqueus Zone: M. priodon, M. minimus, Ct. aff. bohemicus
LOCALITY 2A_ Rock River, south branch; 66°48’, 136°16’W. Note: collected in 1962, not measured,
but graptolites collected in stratigraphic succession from oldest to youngest.
Collection 1F, atavus Zone?: C. innotatus obesus, C. rectangularis, C. normalis, D. cf. modestus, D. cf.
elongatus, G. enodis cf. linearis, O. acuminatus, Cy. vesiculosus, A. strachani.
Collection 2F, acinaces Zone: C. innotatus obesus, C. normalis, Cy. cf. vesiculosus penna, G. ex. gr.
tamariscus, Cy. sp., monograptid indet.
Collection 3F, turriculatus Zone: M. exiguus, M. turriculatus, M. proteus, M. marri, Mon. vomerina cf.
crenulata, Ret. geinitzianus angustidens, ?Div. sp.
Collection 4F, spiralis Zone: M. marri, M. proteus, M. cf. griestoniensis, St. grandis grandis, ?Div. sp.
Collection 5F, spiralis Zone: M. spiralis, M. marri, M. tullbergi spiraloides, M. cf. priodon, Mon. cf.
vomerina crenulata, Ret. geinitzianus angustidens, St. grandis grandis, St. cf. longus, ?Div. sp., Ps. sp.
Collection 6F, spiralis Zone: M. priodon, M. spiralis, St. grandis imperfectus, Ct. sp.
Collection 7F, spiralis Zone: M. spiralis, M. priodon, M. cf. marri, M. tullbergi spiraloides, M. cf.
praecedens, ?Pl. sp., ?Div. sp.
Collection 8F, spiralis Zone: M. spiralis, M. cf. priodon, Mon. cf. griestoniensis, St. grandis grandis,
PES sp
Collection 9F, spiralis Zone: M. spiralis, M. priodon, Mon. vomerina cf. crenulata, Ret. sp., ?Div.
ramosus
Collection 10F,spiralis Zone: M. spiralis, M. cf. priodon, M. tullbergi spiraloides, Mon. ex. gr.
vomerina, Ret. geinitzianus angustidens, St. sp., ?Div. cf. ramosus
Collection 11F, sakmaricus-laqueus Zone: M. cf. priodon, Mon. ex. gr. vomerina, Ret. geinitzianus
geinitzianus, Ret. g. anugstidens, St. grandis grandis, Ct. cf. sakmaricus
LOCALITY 2B Rock River, same as 2A, measured in 1978.
Collection at 241 m, acinaces Zone: Cy. vesiculosus, C. cf. innotatus, C. cf. rectangularis, D. elongatus,
A. strachani
Collection at 243 m, acinaces Zone: D. elongatus?, C. sp., C. innotatus, G. ct. tamariscus linearis, Cy.
vesiculosus, Dm. confertus swanstoni, L. cf. acinaces
Collection at 244 m, gregarius Zone: Dm. physophora alaskensis, G. tamariscus linearis, C. normalis, C.
innotatus obesus, Dm. cf. physophora, G. cf. lanpheri, Cy. vesiculosus, Cr. gregarius arcuatus, L. cf.
acinaces
Collection at 245 m, gregarius Zone: L. cf. acinaces, G. sp., G. tamariscus cf. magnus, C. rectangularis,
C. innotatus obesus, Cy. vesiculosus
Collection at 247 m, gregarius Zone: G. tamariscus (s.1.), C. cf. rectangularis, Cy. vesiculosus
Collection at 249 m, gregarius Zone: G. tamariscus magnus, G. sp.,C. medius, Cy. vesiculosus, ?Dm. ex
145
gr. physophora, Dm. confertus swanstoni, A. cf. gracilis, A. cf. atavus, L. cf. acinaces
Collection at 254 m, gregarius Zone: Cr. gregarius L. cf. acinaces, C. ex gr. tamariscus, C. cf.
miserabilis, C. cf. rectangularis, Cy. vesiculosus, Cy. sp., Dm. physophora?
Collection at 255 m, gregarius Zone: Cr. hipposideros, Cr. cf. cyphus, G. incertus, ?C. cf. miserabilis
Collection at 282 m, turriculatus Zone: M. turriculatus, M. cf. conspectus, M. sp. indet., Pr. cf. nudus,
spr
Collection at 287 m, turriculatus Zone: M. proteus, M. turriculatus, M. rickardsi minor, M. exiguus
primulus, M. runcinatus richardsonensis subsp. nov., Pr. cf. nudus, P. elongatus, ?Ps. sp.
Collection at 293 m, turriculatus Zone: M. proteus, M. marri, M. exiguus primulus, M. turriculatus, M.
cf. rickardsi minor, Ps. sp.
Collection at 302 m, turriculatus Zone: M. proteus, M. marri, M. exiguus primulus, M. turriculatus, M.
spiralis?, Pr. sp., Ps. obesus obesus
Collection at 306 m, spiralis Zone: M. cf. marri, M. spiralis cf. contortus, M. cf. sartorius
Collection at 309 m, spiralis Zone: M. spiralis cf. contortus, M. cf. sartorius, M. cf. marri, Mon. sp.,
Ret. geinitzianus
Collection at 315 m, spiralis Zone: M. spiralis, M. cf. marri, Mon. sp., Ret. geinitzianus
Collection at 323 m, spiralis Zone: M. spiralis, M. marri, M. exiguus primulus, M. cf. proteus, Mon. sp.,
Ret. geinitzianus angustidens
Collection at 326 m, spiralis Zone: M. marri, M. spiralis, M. cf. sartorius, M. cf. proteus, Mon. sp., Pr.
sp., St. grandis grandis, Ps. obscurus
Collection at 345 m, spiralis Zone: M. spiralis, M. cf. speciosus, Mon. sp., Ret. geinitzianus geinitzianus,
Ret. sp.
LOCALITY 3 Tetlit Creek, tributary of Road River, and type section of Road River Formation: 66°44'N,
135°47'W.
Collection at 133 m, acinaces Zone: C. innotatus cf. obesus, C. rectangularis, D. sp., Pc. sp., Cy.
vesiculosus, A. strachani
Collection at 136m, gregarius Zone: Cr. gregarius arcuatus, C. medius, C. innotatus, C. cf.
rectangularis, D. sp., G. ex gr. tamariscus, Dm. cf. physophora, Dm. sp., Cy. cf. vesiculosus
Collection at 138 m, triangulatus or magnus? Zone: C. cf. rectangularis, G. sp., M. cf. sudburiae, R.
approximatus, R. cf. richteri
Collection at 139 m, argenteus Zone: M. millepeda, M. cf. sudburiae, C. cf. medius, O. cf. cyperoides, R.
cf. approximatus, R. longispinus, R. sp.
Collection at 142 m, convolutus Zone: R. cf. longispinus, R. orbitus, ?R. phleoides, M. cf. cygneus, M.
cf. communis, Pr. cf. variabilis, O. obuti, Ret. sp.
Collection at 144 m, turriculatus Zone: M. cf. decipiens, M. turriculatus, M. cf. intermedius, Pr.
regularis, P. cf. hispanicus, R. cf. hybridus gracilis
Collection at 148 m, turriculatus Zone: Pr. sp., M. exiguus primulus, M. cf. priodon, M. cf. spiralis, M.
cf. planus, Ret. sp., ?Div. sp.
Collection at 168 m, spiralis Zone: M. spiralis, M. cf. decipiens, Mon. sp.
Collection at 182 m, spiralis Zone: Ret. geinitzianus angustidens, M. spiralis, M. cf. priodon, Ps.
obscurus, monograptid indet.
Collection at 185 m, spiralis Zone: St. grandis grandis, Ret. geinitzianus angustidens, M. cf. priodon, M.
spiralis, Mon. ex gr. vomerina
Collection at 187 m, spiralis Zone: Mon. sp., M. spiralis, M. cf. priodon, St. grandis grandis
Collection at 192 m, spiralis Zone: Ret. geinitzianus angustidens
Collection at 213 m, sakmaricus-laqueus Zone: Ct. cf. lapworthi, M. spiralis, M. cf. parapriodon, Mon.
cf. vomerina, Ret. geinitzianus angustidens
Collection at 215 m, sakmaricus-laqueus Zone: Ct. sakmaricus, Ret. geinitzianus angustidens, Ct. cf.
lapworthi, M. speciosus, Mon. sp., St. grandis imperfectus
Collection at 216 m, sakmaricus-laqueus Zone: Ct. aff. lapworthi, Mon. cf. linnarssoni, Mon. cf.
vomerina, M. parapriodon, M. cf. speciosus, Ret. sp.
Collection at 217 m, sakmaricus-laqueus Zone: Ct. cf. lapworthi, Ct. sakmaricus, Ret. geinitzianus
angustidens, M. spiralis, M. sp., M. speciosus, St. sp., Mon. sp.
Collection at 219 m, sakmaricus-laqueus Zone: Ct. sakmaricus, Ct. cf. lapworthi, Ret. geinitzianus
angustidens, Ret. g. geinitzianus, St. grandis imperfectus.
Collection at 220 m, sakmaricus-laqueus Zone: Ct. aff. sakmaricus (sp. nov.?), M. cf. speciosus, M.
priodon, M. sp., Ret. geinitzianus angustidens
146
Collection at 223 m, sakmaricus-laqueus Zone: Ct. cf. laqueus, M. priodon, Mon. sp.
Collection at 225 m, sakmaricus-laqueus Zone: Mon. sp., Ct. sakmaricus, Ct. cf. laqueus
Collection at 228 m, sakmaricus-laqueus Zone: Ct. cf. laqueus
LOCALITY 4. Road River, east-central Richardson Mountains; approximately 66°38’N, 135°40’W. Two
collections separated by 59.4 m (195 ft) strata.
Collection 1F, acinaces Zone: Cy. vesiculosus, C. cf. innotatus, C. cf. rectangularis, Dm. sp., A.
strachani
Collection 2F, spiralis Zone: Ret. geinitzianus angustidens, M. cf. spiralis, St. sp.
LOCALITY 5 Unnamed creek, west side of Richardson Mountains; approximately 66°32'N, 136°13'W.
A single *‘spot’’ collection.
gregarius Zone: C. normalis, ?Cy. vesiculosus, Dm. physophora alaskensis, monograptid indet.
LOCALITY 6 Peel River, upper canyon, southwestern side of Richardson Mountains; 65°53’N,
135°43’W. Note: Because of the importance of this section, it was measured twice, once in 1976 and again
in 1977. Because of the problems of precise duplications of measurements and collections, and the
somewhat differing faunas of the two collections, the collections of 1976 and 1977 are listed separately, as
6A and 6B. Because the section was originally measured in feet, both metres and feet are given.
LOCALITY 6A_ (1976 Collections)
Collection at 451.7 m (1482 ft): Ashgillian graptolites
Collection at 452.6 m (1485 ft), acuminatus Zone: C. normalis, C. cf. rectangularis, O. acuminatus, ?Rh.
sp., D. aff. elongatus, G. cf. gnomus
Collection at 453.8 m (1489 ft), acuminatus Zone: C. normalis, C. aff. pacificus pilosus, C. ex gr.
innotatus, G. cf. lanpheri, G. cf. gnomus, O. acuminatus
Collection at 454.8 m (1492 ft), acuminatus Zone: C. normalis, D. modestus diminutus, G. cf. lanpheri,
G. sp., O. acuminatus
Collection at 455.4 m (1494 ft), acuminatus Zone: C. normalis, C. cf. rectangularis, G. cf. lanpheri, O.
acuminatus
Collection at 456 m (1496 ft), atavus Zone: C. normalis, C. innotatus, C. rectangularis, ?Cy. vesiculosus,
D. cf. sp. A Churkin and Carter, G. ex gr. tamariscus
Collection at 457.5 m (1501 ft), atavus Zone: C. normalis, C. cf. rectangularis, D. sp., G. tamariscus
magnus
Collection at 460 m (1509 ft), acinaces Zone: Cy. vesiculosus, C. innotatus obesus, C. cf. rectangularis,
C. normalis, G. cf. enodis enodis, G. cf. tamariscus magnus, Dm. confertus swanstoni, Pc. hughesi, A.
strachani
Collection at 461.5 m (1514 ft), acinaces Zone: G. cf. lanpheri, C. innotatus, C. rectangularis, ?Cy.
vesiculosus, Dm. sp., Pc. hughesi, L. acinaces, A. cf. gracilis, monograptid indet.
Collection at 465.1 m (1526 ft) gregarius Zone: Cr. gregarius, L. cf. acinaces, Pb. cf. angustus, ?Cy.
vesiculosus, O. obuti, Dm. confertus swanstoni, D. cf. elongatus, G. enodis latus, G. cf. tamariscus
tamariscus
Collection at 468.2 (1536 ft), gregarius Zone: G. ex gr. tamariscus, G. ex gr. enodis, G. sp., D. sp., M.
revolutus, Cr. hipposideros
Collection at 470.3 m (1543 ft), gregarius Zone: G. laciniosus, G. sp., A. cf. strachani, Cr. gregarius
arcuatus, C. rectangularis, C. normalis, M. cf. revolutus, O. cf. obuti, Pb. sp.
Collection at 474 m (1555 ft), gregarius Zone: Cr. gregarius arcuatus, G. laciniosus, G. sp., ?Rh. sp.,
2D. sp., Pr. sp. 2 (of Hutt, 1975), M. cf. revolutus, monograptid indet.
Collection at 477 m (1565 ft), triangulatus Zone: M. cf. elongatus, M. sp., Cr. gregarius, C. cf.
rectangularis, C. normalis, R. longispinus, retiolitid indet.
Collection at 480 m (1574 ft) triangulatus Zone: R. approximatus, 2D. sp., C. normalis, monograptid
indet.
Collection at 480.4 m (1576 ft), triangulatus Zone: C. normalis, C. cf. rectangularis, M. cf. triangulatus
separatus , monograptid indet., R. approximatus, R. sp., G. sp.
Collection at 481.9 m (1581 ft), triangulatus Zone: L. cf. inexpeditus, M. revolutus, monograptid indet.
C. cf. rectangularis, D. modestus, M. cf. tenuissmus, R. cf. approximatus, R. sp.
Collection at 485.9 m (1594 ft), magnus Zone?: Rh. cf. toernquisti, ?Rh. sp., M. involutus, M. ct.
revolutus, M. sp., Cr. gregarius, C. cf. laciniosus, C. sp.
147
Collection at 488 m (1601 ft), magnus Zone?: Cr. cf. gregarius, M. involutus, M. revolutus, M.
triangulatus fimbriatus, G. cf. laciniosus, R. sp.,C. sp., ?Pc. sp., Pb. angustus
Collection at 491.4 m (1612 ft), argenteus Zone?: M. aff. cygneus (sensu Obut and Sobolevskaya, 1967),
M. millepeda, M. cf. argenteus argenteus, M. cf. lobiferus, R. sp.,R. orbitus, ?Ps. sp.,G. cf. laciniosus,
p. ovatoelongatus, P. cf. minor, R. phleoides
Collection at 496.2 m (1628 ft), convolutus Zone: M. communis, M. sidjachenkoi, M. convolutus, P.
folium, P. cf. minor, D. thuringiacus, O. cf. inopinatus, G. tamariscus tamariscus, G. cf. enodis, Pc.
hughesi, R. sp., R. cf. hybridus
Collection at 498.7 m (1636 ft), convolutus Zone: M. convolutus, M. communis, M. aff. cygneus (sensu
Obut and Sobolevskaya, 1967), M. sp., P. folium, P. cf. intermedius, D. thuringiacus, C. cf. medius, O.
cf. insectiformis, G. tamariscus tamariscus, R. cf. approximatus, R. sp.
Collection at 502.3 m (1648 ft), convolutus Zone: M. convolutus, M. lobiferus harpago, M. clingani, M.
aff. cygneus (sensu Obut and Sobolevskaya, 1967), M. sidjachenkoi, M. sp., G. ex gr. tamariscus, R. cf.
richteri, O. insectiformis, C. cf. medius, D. thuringiacus, P. minor
Collection at 507.8 m (1666 ft), convolutus Zone: D. cf. thuringiacus, R. approximatus geinitzi, R.
richteri, R. longispinus, ?Div. spp., M. sidjachenkoi, M. aff. cygneus (sensu Obut and Sobolevskaya,
1967), 2M. convolutus, M. clingani, M. cf. lobiferus harpago, Pt. cf. undulatus, G. ex gr. tamaricus, Ps.
cf. obesus, Ceph. sp., R. phleoides, P. sp.,C. medius, Pr. cf. regularis
Collection at 512.4 m (1681 ft), convolutus Zone: M. aff. cygneus (sensu Obut and Sobolevskaya, 1967),
M. sidjachenkoi, M. communis cf. communis, M. buddingtoni, Pr. regularis, Pr. sp. 1 (of Hutt, 1975), R.
phleoides, R. orbitus, P. intermedius, P. cf. palmeus praecedens, D. sp., Pc. cf. undulatus (sensu Churkin
and Carter, 1970); €. sp.
Collection at 519.4 m (1704 ft), sedgwicki Zone: R. perfectus, R. rostratus sp. nov., Pr. regularis, Pr.
sp., M. cf. proteus, M. cf. denticulatus, M. pseudobecki, M. cf. mirus, M. cf. tenuissmus, M. cf. marri,
Ps. obesus obesus
Collection at 521.8 m (1712 ft), turriculatus Zone: M. sedgwicki, M. decipiens valens, M. turriculatus,
Pr. regularis, Pr. cf. nudus, P. cf. ovatus, P. tenuis, P. ovatoelongatus, P. altissimus, P. elongatus, Ps.
obesus obesus, R. maximus
Collection at 523 m (1716 ft), turriculatus Zone: P. cf. palmeus palmeus, P. ovatoelongatus, M. ct.
decipiens valens, M. turriculatus, M. exiguus primulus, M. spiralis, M. spp., Pr. nudus, Pr. cf. variabilis
Collection at 526 m (1726 ft), turriculatus Zone: M. turriculatus, M. cf. decipiens, M. cf. sedgwicki, M.
ex gr. exiguus, M. sp., G. sp., Pr. cf. regularis, P. sp.
Collection at 528.5 m (1734 ft), turriculatus Zone: P. sp., ?Div. ramosus, G. sp., M. rickardsi minor, M.
turriculatus, M. cf. planus
Collection at 536.1 m (1759 ft), turriculatus Zone: M. exiguus primulus, M. turriculatus, M. cf.
conspectus, M. cf. pandus
Collection at 541.3 m (1776 ft), turriculatus Zone: M. exiguus cf. primulus, M. cf. proteus, ?D. sp.
Collection at 544.4 m (1786 ft), turriculatus Zone: M. exiguus primulus, M. cf. conspectus, M. falx, M.
cf. pandus, M. turriculatus, Ps. sp., Ret. sp., P. cf. hispanicus
Collection at 553.8 m (1817 ft), turriculatus Zone: M. exiguus primulus, M. tullbergi spiraloides, M.
turriculatus, M. marri, M. sp., Mon. ex gr. vomerina, Ps. obesus obesus
Collection at 559.3 m (1835 ft), turriculatus Zone: M. cf. sartorius, M. proteus, M. exiguus primulus, M.
cf. pandus
Collection at 579.7 m (1902 ft), spiralis Zone: M. spiralis, M. priodon, M. cf. sartorius, Mon. ex gr.
vomerina
LOCALITY 6B (1977 collections)
Collection at 454.2 m (1490 ft), Ashgillian graptolites
Collection at 454.5 m (1491 ft), acuminatus Zone: C. normalis, C. cf. miserabilis, C. trifilis, O.
acuminatus, G. sp.
Collection at 454.8 m (1492 ft), acuminatus Zone: D. modestus, O. acuminatus, C. rectangularis, C.
normalis, G. sp., ?Ak. sp.
Collection at 455.1 m (1493 ft), acuminatus Zone: C. rectangularis, C. normalis, D. aff. mucroterminatus
Collection at 455.4 m (1494 ft), acuminatus Zone: O. acuminatus, C. normalis, C. aff. pilosus, G. cf.
gnomus
Collection at 456 m (1496 ft), acuminatus Zone: O. acuminatus, C. aff. pilosus, C. normalis, D. modestus
diminutus, O. eberleini, Ak. sp., G. cf. lanpheri.
148
Collection at 456.3 m (1497 ft), acuminatus Zone: C. normalis, C. rectangularis, G. cf. lanpheri, O.
acuminatus, D. modestus diminutus , ?Ak. ascensus
Collection at 456.9 m (1499 ft), acuminatus Zone: O. acuminatus, C. normalis, D. sp., D. modestus
diminutus, C. rectangularis
Collection at 457.8 m (1502 ft), atavus Zone?: C. rectangularis, C. normalis, C. innotatus, G. laciniosus,
G. lanpheri, ?Cy. vesiculosus, Pc. hughesi
Collection at 459 m (1506 ft), atavus Zone: C. rectangularis, C. innotatus obesus, Cy. vesiculosus, ?Pc.
hughesi, G. sp., G. ex gr. tamariscus
Collection at 459.6 m (1508 ft), atavus Zone: C. rectangularis, C. cf. normalis, D. cf. elongatus, ?Cy.
vesiculosus, monograptid indet.
Collection at 460.6 m (1511 ft), acinaces Zone: C. rectangularis, C. innotatus, C. innotatus obesus, C.
normalis, Cy. vesiculosus, A. strachani, L. cf. acinaces, Pc. hughesi, Dm. confertus swanstoni, O.
eberleini
Collection at 461.5 m (1514 ft), acinaces Zone: Pc. hughesi, C. medius, C. innotatus, C. rectangularis,
Cy. vesiculosus, Dm. confertus swanstoni, A. strachani, G. laciniosus, G. tamariscus magnus
Collection at 463 m (1519 ft), acinaces Zone: Pc. hughesi, C. medius, C. rectangularis, C. innotatus
obesus, D. cf. elongatus, G. tamariscus magnus, G. enodis, A. strachani, O. eberleini, Dm. confertus
swanstoni, Dm. physophora alaskensis, Cy. vesiculosus
Collection at 469.4 m (1540 ft), gregarius Zone: C. cf. laciniosus, Cr. hipposideros, Pc. hughesi,
monograptid indet., C. rectangularis?, C. sp.
Collection at 471.5 m (1547 ft), gregarius Zone: Cr. cf. cyphus, Cr. hipposideros, Cr. gregarius
arcuatus, Cr. gregarius, C. rectangularis, C. cf. normalis, C. sp. nov.,? D. cf. elongatus, D. cf.
mucroterminatus, D. cf. magnus, ‘‘M.’’ cf. incommodus, M. revolutus, G. incertus, Dm. cf. physophora,
O. inopinatus
Collection at 472.7 m (1551 ft), gregarius Zone: C. cf. rectangularis, Cr. gregarius, Cr. gregarius
arcuatus, G. laciniosus, G. cf. tamariscus magnus
Collection at 475.5 m (1560 ft), gregarius or triangulatus Zone: Cr. gregarius arcuatus, Cr. aff.
gregarius, G. incertus, C. rectangularis, ‘‘M.’’ cf. incommodus, M. triangulatus, M. aff. fragilis, M. sp.,
DD. sp. 2
Collection at 482.5 m (1583 ft), triangulatus Zone: M. revolutus, M. triangulatus fimbriatus, M.
communis rostratus?, M. cf. tenuissmus, M. cf. involutus, M. inexpeditus, C. cf. rectangularis, R. cf.
peregrinus, G. tamariscus magnus
Collection at 487.4 m (1599 ft), triangularis Zone: C. rectangularis, C. innotatus, C. sp., M. cf.
triangulatus, M. cf. involutus, M. cf. revolutus, M. cf. communis, M. communis, M. millepeda, Cr.
gregarius, P. intermedius, D. cf. thuringiacus, R. sp.
Collection at 489.2 m (1605 ft), triangulatus or magnus? Zone: M. cf. cygneus (sensu Obut and
Sobolevskaya, 1967), M. inexpeditus, M. sp., M. cf. triangulatus fimbriatus, Cr. gregarius, G. cf.
incertus
Collection at 490.7 m (1610 ft), argenteus Zone: G. cf. tamariscus magnus, R. orbitus, ‘‘M.’’ cf. fragilis,
M. aff. cygneus (sensu Obut and Sobolevskaya, 1967), M. triangulatus fimbriatus, D. sp., O. cf.
inopinatus
Collection at 495.9 m (1627 ft), convolutus Zone: M. aff. cygneus (sensu Obut and Sobolevskaya, 1967),
M. communis, P. folium, G. cf. tamariscus, D. cf. thuringiacus, C. sp.,R. phleoides, R. sp.,O. cf. obuti
Collection at 506.3 m (1661 ft), convolutus Zone: M. atf. cygneus (sensu Obut and Sobolevskaya, 1967),
M. sp. (lobate thecae), Pc. undulatus, P. cf. intermedius, D. cf. thuringiacus, R. sp.
Collection at 508.4 m (1668 ft), convolutus Zone: R. orbitus, R. phleoides, P. cf. intermedius, D. cf.
thuringiacus, Pc. undulatus, M. aff. cygneus (sensu Obut and Sobolevskaya, 1967), M. cf. tenuissmus
Collection at 513.6 m (1685 ft), sedgwicki Zone: R. cf. hybridus, R. distans, R. maximus, R. linnaei, Ps.
obesus obesus, Pr. regularis, Pr. cf. nudus, M. turriculatus, M. communis, M. cf. proteus, M. cf.
circularis, M. sedgwicki, P. elongatus
Collection at 515.1 m (1690 ft), sedgwicki Zone: Pr. regularis, R. nudus, R. perfectus, R. rostratus sp.
nov.,R. cf. hybridus, R. approximatus geinitzi, R. cf. distans, R. cf. approximatus, M. sedgwicki, M. cf.
tenuissmus, M. cf. mirus, M. sp., M. aff. cygneus (sensu Obut and Sobolevskaya, 1967), M. sp. (nodifer
type), ?Ps. sp., P. elongatus
Collection at 516.3 m (1694 ft), turriculatus Zone: M. decipiens valens, M. sedgwicki, M. involutus, M.
cf. elongatus, Pr. regularis, R. maximus, D. sp., Ps. cf. obesus, P. ovatoelongatus, P. sp.
Collection at 516.9 m (1696 ft), turriculatus Zone: Pr. regularis, Pr. nudus, M. cf. runcinatus, M.
decipiens valens, M. turriculatus, M. exiguus primulus, M. cf. sedgwicki, M. sp., Ps. sp., P. elongatus,
P. cf. palmeus palmeus
149
Collection at 517.9 m (1699 ft), turriculatus Zone: M. decipiens valens, M. exiguus primulus, M.
sedgwicki, M. turriculatus, Pr. nudus, Pr. regularis, P. cf. tenuis, P. cf. palmeus clavatus, Ps. sp.
Collection at 518.8 m (1702 ft), turriculatus Zone: M. decipiens valens, M. turriculatus, M. exiguus
primulus, M. cf. circularis, Pr. regularis, Pr. nudus, P. wilsoni, P. palmeus clavatus, P. cf. palmeus
palmeus, Ps. obesus reticulatus
Collection at 523 m (1716 ft), turriculatus Zone: M. planus, M. pseudobecki, M. proteus, M. cf. halli, M.
turriculatus, M. falx, P. cf. altissimus, Pr. nudus, Pr. cf. regularis, R. spp., G. cf. tamariscus
Collection at 528.8 m (1735 ft), turriculatus Zone: M. pseudobecki, M. exiguus primulus, M. turriculatus,
M. planus obtusus, M. halli, M. cf. conspectus, M. cf. marri, R. linnaei, Mon. ex gr. vomerina
Collection at 531.9 m (1745 ft), turriculatus Zone: M. exiguus primulus, M. turriculatus, M. cf. pandus,
M. planus obtusus, R. linnaei, P. altissimus, Ps. sp., Ps. cf. obesus, ?Div. ramosus, Pr. nudus
Collection at 548.9 m (1801 ft), turriculatus Zone: M. marri, M. exiguus primulus, M. turriculatus, M.
proteus, Ps. sp., Ps. obesus reticulatus
Collection at 559.3 m (1835 ft), turriculatus Zone: Pr. initialis, M. exiguus primulus, M. cf. priodon, M.
turriculatus, M. cf. spiralis, M. sp., Div. sp., Ret. geinitzianus (sensu lato)
Collection at 570.9 m (1873 ft), spiralis Zone: M. spiralis cf. contortus, M. priodon, Div. sp., Ret. sp.
Collection at 582.2 m (1910 ft), spiralis Zone: M. cf. parapriodon, M. spiralis cf. contortus, Mon. ex gr.
vomerina
Collection at 602.6 m (1977 ft), spiralis Zone: M. spiralis, 2Div. ramosus, monoclimacid, Ret.
geinitzianus angustidens
Collection at 611. 4m (2006 ft), spiralis Zone: M. spiralis, M. cf. sartorius, M. sp.,M. curvus, M. falx,
Mon. ex gr. vomerina, Ret. geinitzianus angustidens
Collection at 612.6 m (2010 ft), spiralis Zone: Ret. geinitzianus angustidens, M. spiralis, Mon. cf.
crenulata, Pr. ex gr. dubius
Collection at 614.2 m (2015 ft), spiralis Zone: M. spiralis, M. cf. sartorius, M. priodon, Mon. ct.
griestoniensis, Ret. geinitzianus angustidens
Collection at 615.7 m (2020 ft), spiralis Zone: ?Div. sp., ?Div. ramosus, Mon. griestoniensis, M. spiralis,
M. priodon, M. cf. continens, Ret. geinitzianus angustidens
Collection at 629.4 m (2065 ft), spiralis Zone: Ret. geinitzianus angustidens, M. priodon, M. spiralis, M.
cf. sartorius, Mon. ex gr. vomerina, Mon. cf. griestoniensis
Collection at 630.9 m (2070 ft), spiralis Zone or sakmaricus-laqueus Zone: M. spiralis (rare), M. cf.
priodon, Mon. ex gr. vomerina, Mon. cf. griestoniensis, Ret. geinitzianus angustidens, St. grandis
imperfectus, ?Div. ramosus
Collection at 635.5 m (2085 ft), sakmaricus-laqueus Zone: Mon. ex gr. vomerina, M. cf. priodon, M.
parapriodon, Ct. aff. lapworthi, ?Div. sp., Ret. geinitzianus angustidens
Collection at 637.3 m (2091 ft), sakmaricus-laqueus Zone: ?Div. sp., St. grandis imperfectus, Ct.
laqueus, Ret. geinitzianus angustidens, M. cf. priodon, M. cf. sartorius, Mon. ex gr. vomerina
Collection at 638.6 m (2095 ft), sakmaricus-laqueus Zone: M. priodon, Mon. linnarssoni, Ret. sp., Ct.
aff. lapworthi
Collection at 640.1 m (2100 ft), sakmaricus-laqueus Zone: M. cf. praecedens, 2H. sp., ?Pl. sp., Mon. cf.
linnarssoni, Ct. laqueus, Ct. aff. lapworthi, ?Ret. balticus
Collection at 641.6 m (2105 ft), sakmaricus-laqueus Zone: Ct. laqueus, M. cf. praecedens
Collection at 642.5 m (2108 ft), sakmaricus-laqueus Zone: M. cf. praecedens, M. cf. parapriodon, Mon.
linnarssoni, Ct. laqueus
LOCALITY 7 Blackstone River, Ogilvie Mountains, east bank: 65°26’N, 137°20’W.
Collection at 36.6 m (120 ft): Ashgillian graptolites
Collection at 53.3 m (175 ft), persculptus Zone?: O. truncatus pauperatus, C. normalis (transitional to C.
miserabilis), C. sp. (long proximal spines), ?7G. sp., D. modestus (very abundant)
Collection at 58.8 m (193 ft), acuminatus Zone: C. normalis, C. rectangularis, C. innotatus cf. obesus, C.
innotatus innotatus, ?Cy. vesiculosus
Collection at 60.7 m (199 ft), acuminatus Zone?: C. rectangularis, C. normalis, C. innotatus cf. obesus,
2Cy. vesiculosus
Collection at 61.3 m (201 ft), acuminatus Zone?: C. rectangularis, C. innotatus cf. obesus, C. Ch:
normalis, G. sp., G. tamariscus magnus
Collection at 61.9 m (203 ft), atavus Zone?: G. tamariscus magnus, Dm. cf. physophora, Pc. sp., A. cf.
gracilis, ?Cy. vesiculosus
Collection at 62.2 m (204 ft), aravus Zone?: Cy. vesiculosus, C. cf. medius, C. innotatus cf. obesus, G.
150
tamariscus magnus, Dm. confertus swanstoni, Pc. hughesi, A. cf. strachani
Collection at 62.5 m (205 ft), acinaces Zone: G. tamariscus magnus, Cy. vesiculosus, Pc. hughesi, C.
medius, C. rectangularis, C. ex gr. innotatus, Dm. confertus swanstoni, Dm. physophora alaskensis, A.
strachani
Collection at 65.5 m (215 ft), argenteus Zone: R. approximatus, R. sp., M. revolutus, M. communis, M.
millepeda, M. involutus, P. ovatoelongatus, Cr. gregarius, P. intermedius, D. cf. elongatus, C. cf.
rectangularis, G. cf. tamariscus, L. cf. acinaces, ?Ps. sp., ?Nymphograptus sp.
Collection at 66.4 m (218 ft), convolutus Zone: R. cf. hybridus, M. cf. crenularis, M. communis, M.
convolutus, M. aff. cygneus (sensu Obut and Sobolevskaya, 1967), M. noyensis, P. folium, P. cf. minor,
P. cf. intermedius, Ret. decurtatus, M. cf. argenteus, G. tamariscus tamariscus, G. cf. gnomus, O.
inopinatus, O. insectiformis, ?Ps. sp.
Collection at 69.2 m (227 ft), convolutus Zone: M. aff. cygneus, M. cf. sedgwicki, M. cf. elongatus, M.
sidjachenkoi, M. communis, M. communis rostratus?, M. convolutus, Ceph. tubulariformis, P. folium, P.
sp., P. orbitus, Pc. undulatus, O. inopinatus, O. insectiformis, D. thuringiacus, G. tamariscus
tamariscus, G. cf. gnomus, M. cf. lobiferus
Collection at 70.4 m (231 ft), convolutus Zone: P. intermedius, P. sp., M. sidjachenkoi, M. clingani, M.
convolutus, M. communis, Ceph. cometa cometa, R. orbitus, G. sp., Pc. undulatus, D. thuringiacus, Pb.
cf. argutus, Pr. nudus
Collection at 72.2 m (237 ft), sedgwicki Zone: Pc. sp., B. aff. pulchellus, P. intermedius, P. elongatus, P.
sp., P. altissimus, R. approximatus geinitzi, R. cf. maximus, Pr. nudus, Pr. regularis, M. cf. undulatus,
M. cf. spiralis, M. sp., M. sedgwicki, ?Ps. sp.
Collection at 74.7 m (245 ft), sedgwicki Zone: ?Div. ramosus, M. spiralis cf. contortus, M. cf. decipiens
valens, M. crenularis, M. cf. sedgwicki, M. pseudobecki, R. linnaei, Pr. cf. regularis, P. intermedius, G.
sp.
Collection at 76.2 m (250 ft), sedgwicki Zone: Pc. undulatus, P. sp., M. decipiens, M. sedgwicki, M. cf.
lobiferus, M. cf. crenularis, M. cf. limatulus, Pr. regularis, O. cf. cyperoides, Mon. sp., Ceph. sp.
Collection at 77.2 m (255 ft), sedgwicki Zone: P. intermedius, P. elongatus, P. altissimus, Pr. cf.
regularis, Pr. cf. nudus, R. cf. perfectus, M. cf. planus, M. cf. dextrorsus, M. sedgwicki, M. spiralis cf.
contortus, Ceph. cometa extrema
Collection at 80.2 m (263 ft), turriculatus Zone: M. decipiens valens, M. cf. dextrorsus, M. cf. decipiens,
M. turriculatus, M. cf. knockensis, M. cf. sedgwicki, R. sp., P. intermedius, P. cf. elongatus, P. cf.
altissmus, ?Pt. perlatus, ? Ps. sp., G. sp.?, Pr. cf. regularis
Collection at 83.8 m (275 ft), turriculatus Zone: M. decipiens valens, M. cf. pseudobecki, M. turriculatus,
M. exiguus cf. primulus, M. spiralis, M. cf. marri, Pr. regularis, P. cf. tenuis, P. sp.
Collection at 85.3 m (280 ft), turriculatus Zone: M. decipiens valens, M. cf. pseudobecki, M. spiralis, M.
halli, M. turriculatus, D. sp., P. ex gr. palmeus, P. cf. elongatus, Pr. cf. regularis
Collection at 86.9 m (285 ft), rurriculatus Zone: M. turriculatus, M. cf. planus, M. cf. pseudobecki, M.
cf. millepeda, ?Div. ramosus, P. sp., P. cf. elongatus
Collection at 88.7 m (291 ft), turriculatus Zone: P. cf. ovatoelongatus, P. elongatus, M. turriculatus, M.
decipiens valens, M. ct. sedgwicki, M. cf. pseudobecki, Pr. cf. regularis, D. sp.
Collection at 89 m (292 ft), turriculatus Zone: M. turriculatus, M. decipiens valens, Pr. cf. regularis
Collection at 91.4 m (300 ft), turriculatus Zone: Ret. perlatus, M. planus obtusus, M. turriculatus, M.
exiguus primulus, M. ct. marri, M. cf. proteus, M. cf. priodon, M. flagellaris, M. cf. sedgwicki, M. cf.
delicatulus, P. altissimus, P. cf. elongatus
Collection at 92.7 m (304 ft), turriculatus Zone: M. marri, M. exiguus primulus, M. turriculatus, M.
proteus, M. runcinatus, Pr. cf. nudus
Collection at 94.8 m (311 ft), turriculatus Zone: P. cf. hispanicus, M. proteus, M. marri, M. turriculatus,
M. exiguus primulus, M. runcinatus richardsonensis subsp. nov.
Collection at 99 m (325 ft), turriculatus Zone: M. proteus, M. turriculatus, M. exiguus primulus, M.
marri, ?Ps. sp.
Collection at 103.6 m (340 ft), spiralis Zone: M. priodon, M. spiralis, Mon. cf. crenulata, St. grandis
grandis
LOCALITY 8 Unnamed tributary of Hart River, 5 km (3 mi) north of Pat Lake, west side of creek:
65°09'N, 136°42'W. Section not measured, but collected in stratigraphic succession.
Collection 1F: Ashgillian graptolites
Collection 2F, acuminatus Zone?: C. innotatus, C. cf. pacificus, C. normalis, C. cf. rectangularis, G.
lanpheri
151
Collection 3F, acinaces Zone: C. normalis, C. rectangularis, C. innotatus, C. cf. pacificus pilosus, O.
acuminatus, Pc. sp., ?Cy. vesiculosus, D. elongatus, G. cf. lanpheri, G. cf. laciniosus, Dm. physopnora
alaskensis, Cr. gregarius arcuatus, A. strachani, A. cf. gracilis, Rh. sp.
LOCALITY 9 Mount Sekwi, central western Mackenzie Mountains, overturned section: 63°20’'N,
128°33'W.
Collection at 654.7 m (2148 ft), acuminatus Zone?: C. normalis, D. cf. modestus
Collection at 547.4 m (1796 ft), turriculatus Zone: M. exiguus primulus, M. turriculatus, M. proteus, M.
cf. praecedens, M. cf. delicatulus
Collection at 527.6 m (1731 ft), turriculatus Zone: M. exiguus primulus, M. turriculatus, M. cf. proteus
Collection at 516.9 m (1696 ft), spiralis Zone: M. spiralis, M. cf. speciosus, Mon. cf. crenulata
Collection at 413 m (1355 ft), spiralis Zone?: Ret. geinitzianus angustidens
Collection at 384 m (1260 ft), sakmaricus-laqueus Zone?: M. priodon, M. cf. parapriodon, Mon.
linnarssonit, Mon. ex gr. vomerina
LOCALITY 10 Delorme Range, Mackenzie Mountains, central region: 62°45’N, 125°15’W. (Collected
by J.E. Etherington, 1965.)
Collection at 768.1 m (2520 ft), convolutus Zone: P. minor, M. clingani
Collection at 774.2 m (2540 ft), turriculatus Zone: M. turriculatus
Collection at 777.2 m (2550 ft), turriculatus Zone: M. turriculatus, M. tullbergi spiraloides, M. cf.
clingani, C. sp., Mon. ex gr. vomerina
Collection at 804.7 m (2640 ft), rurriculatus Zone: M. exiguus primulus
Collection at 861.1 m (2825 ft), turriculatus Zone: M. exiguus primulus, M. cf. priodon, retiolitid indet.
Collection at 906.8 m (2975 ft), spiralis Zone: M. priodon
Collection at 911.4 m (2990 ft), spiralis Zone: M. priodon, M. spiralis, M. cf. spinulosus, Ret.
geinitzianus angustidens, ?Ct. sp.
Collection at 912.3 m (2993 ft), spiralis Zone?: M. priodon
Collection at 935.7 m (3070 ft), spiralis Zone?: M. priodon, M. spiralis, St. grandis cf. maior
Collection at 969.9 m (3182 ft), spiralis Zone?: M. spiralis
Collection at 973.2 m (3193 ft), spiralis Zone?: Ret. sp.
Collection at 976.9 m (3205 ft), spiralis Zone?: M. spiralis, Ret. sp., Ps. giganteus, Mon. ex gr. vomerina
Collection at 986 m (3235 ft), spiralis Zone?: Ret. geinitzianus angustidens
Collection at 1027.2 m (3370 ft), sakmaricus-laqueus Zone: Ct. aff. lapworthi, Mon. cf. greistoniensis
Collection at 1028.4 m (3374 ft), sakmaricus-laqueus Zone: M. cf. praecedens, Mon. cf. griestoniensis,
2Ct. aff. lapworthi
Collection at 1031.4 m (3384 ft), sakmaricus-laqueus Zone: M. praecedens, Ct. aff. lapworthi
LOCALITY 11 Whittaker Range, Mackenzie Mountains, central region: 62°28'30''N, 124°48’W.
(Collected by J. E. Etherington, 1965.)
Collection at 728.5 m (2390 ft), spiralis Zone: M. priodon, M. spiralis, Ret. geinitzianis angustidens, St.
grandis maior
Collection at 752.2 m (2468 ft), spiralis Zone: ?St. grandis
Collection at 762 m (2500 ft), spiralis Zone: St. grandis
Collection at 765 m (2510 ft), spiralis Zone: M. spiralis, Mon. crenulata
Collection at 768.1 m (2520 ft), spiralis Zone: M. priodon
Collection at 769.6 m (2525 ft), spiralis Zone: St. grandis maior
Collection at 774.2 m (2540 ft), spiralis Zone: M. spiralis
Collection at 795.5 m (2610 ft), spiralis Zone: M. spiralis
Collection at 798.6 m (2620 ft), spiralis Zone: M. cf. priodon, St. grandis grandis
Collection at 802.8 m (2634 ft), spiralis Zone: M. cf. priodon
Collection at 805.3 m (2642 ft), spiralis Zone: M
Collection at 814.4 m (2672 ft), spiralis Zone: M. priodon
Collection at 815.9 m (2677 ft), spiralis Zone: M. spiralis, M. priodon
Collection at 819.9 m (2690 ft), spiralis Zone: Mon. cf. crenulata
Collection at 823 m (2700 ft), spiralis Zone: M. spiralis, M. cf. priodon, Mon. cf. crenulata
Collection at 827.5 m (2715 ft), spiralis Zone: M. spiralis, M. priodon
Collection at 836.7 m (2745 ft), spiralis Zone: M. spiralis, M. priodon
. priodon
152
Collection at 839.7 m (2755 ft), spiralis Zone: M. spiralis, M. cf. spinulosus, Mon. ct. crenulata
Collection at 844.3 m (2770 ft), spiralis Zone: M. priodon, M. cf. spinulosus, retiolitid indet.
Collection at 855.6 m (2807 ft), spiralis Zone: M. spiralis, Ret. geinitzianus angustidens
Collection at 856.6 m (2810 ft), spiralis Zone: Mon. cf. vomerinus vomerina, M. cf. falx
Collection at 861.1 m (2825 ft), spiralis Zone: Mon. cf. crenulata
Collection at 868.7 m (2850 ft), spiralis Zone: M. cf. spiralis
Collection at 892.5 m (2928 ft), spiralis Zone: M. priodon, Pr. dubius
Collection at 896.1 m (2940 ft), spiralis Zone: M. priodon, Pr. ex gr. dubius, Mon. cf. crenulata
Collection at 900.7 m (2955 ft), spiralis Zone: M. cf. priodon, Pr. dubius dubius
Collection at 905.3 m (2970 ft), spiralis Zone: M. cf. priodon, Pr. dubius dubius, Mon. cf. crenulata
Collection at 910.7 m (2988 ft), spiralis Zone: M. priodon, Mon. cf. crenulata
Collection at 914.4 m (3000 ft), spiralis Zone: Pr. cf. dubius, Mon. ex gr. vomerinus
Collection at 915.9 m (3005 ft), spiralis Zone: M. cf. priodon
Collection at 922 m (3025 ft), highest recognizable Llandovery (zonal assignment not possible): M.
priodon, M. spiralis, Pr. cf. dubius, Mon. cf. crenulata
LOCALITY 12A_ Clearwater Creek, tributary of South Nahanni River, southern Mackenzie Mountains,
west bank of creek: 61°35'N, 125°35'W. (Collected by J.E. Etherington, 1966.)
Collection at 13.7 m (45 ft), persculptus or acuminatus Zone: C. miserabilis
Collection at 15.2 m (50 ft), persculptus or acuminatus Zone:
Collection at 18.3 m (60 ft), persculptus or acuminatus Zone:
Collection at 19.8 m (65 ft), persculptus or acuminatus Zone:
, C. cf. innotatus
Go Sp:
. miserabilis, G. sp. 20. sp.
1G. Spe
. miserabilis
_ miserabilis
Collection at 24.4 m (80 ft), persculptus or acuminatus Zone: C. miserabilis
Collection at 25.9 m (85 ft), persculptus or acuminatus Zone:
Collection at 30.5 m (100 ft), acuminatus Zone: C. miserabilis,
sp.
Collection at 32 m (105 ft), acuminatus Zone: C. miserabilis, C. innotatus obesus, G. sp.
Collection at 33.5 m (110 ft), acuminatus Zone: C
Collection at 35.1 m (115 ft), acuminatus Zone: C
Collection at 36.6 m (120 ft), acuminatus Zone: C
Collection at 38.1 m (125 ft), acuminatus Zone: C. miserabilis, C. innotatus cf. obesus
Collection at 41.1 m (135 ft), acuminatus Zone: C. normalis, C. miserabilis, C. aff. trifilis
C
Cc
G
C
. miserabilis
G
C
Cc
Collection at 21.3 m (70 ft), persculptus or acuminatus Zone: C. miserabilis
(C
C
C. cf. innotatus obesus, C. aff. trifilis, G.
. miserabilis, C. innotatus obesus, C. aff. trifilis
_ innotatus, C. cf. miserabilis, G. cf. enodis latus
_ miserabilis, C. innotatus cf. obesus
Collection at 42.7 m (140 ft), acuminatus Zone:
Collection at 44.2 m (145 ft), acuminatus Zone:
Collection at 45.7 m (150 ft), acuminatus Zone: C. normalis, C. innotatus cf. obesus
Collection at 47.2 m (155 ft), acuminatus Zone: C. normalis, C. aff. trifilis
Collection at 64 m (210 ft), convolutus Zone?: G. sp., R. sp., M. cf. convolutus, M. cf. communis
Collection at 65.5 m (215 ft), sedgwicki or turriculatus Zone: P. cf. hispanicus, M. cf. lobiferus harpago,
M. cf. turriculatus, M. cf. clingani, Pr. cf. nudus, ?Div. ramosus
Collection at 67.1 m (220 ft), turriculatus Zone: M. flagellaris, M. marri, M. turriculatus, M. sedgwicki?,
P. palmeus (s.1.)
Collection at 68.6 m (225 ft), turriculatus Zone: M. flagellaris, M. cf. pandus, M. turriculatus
Collection at 70.1 m (230 ft), turriculatus Zone?: M. spiralis, M. turriculatus, M. cf. pandus
Collection at 73.2 m (240 ft), spiralis Zone: M. spiralis, M. pandus, Mon. ex gr. vomerina, Ret.
geinitzianus angustidens
Collection at 76.2 m (250 ft), spiralis Zone: M. marri, M. priodon, M. spiralis, Mon. cf. griestoniensis,
Mon. ex gr. vomerina, Ret. geinitzianus angustidens
Collection at 77.7 m (255 ft), spiralis Zone: M. cf. dextrorsus, M. spiralis, Mon. ex gr. vomerina
Collection at 79.2 m (260 ft), spiralis Zone: M. curvus, M. priodon, M. spiralis, Mon. griestoniensis, Ret.
geinitzianus angustidens
Collection at 82.3 m (270 ft), spiralis Zone: M. cf. spiralis
Collection at 83.8 m (275 ft), sakmaricus-laqueus Zone: M. priodon, M. cf. praecedens, Ct. aff.
lapworthi, St. sp., Mon. ex gr. vomerina, Ret. geinitzianus angustidens
Collection at 85.3 m (280 ft), sakmaricus-laqueus Zone: M. spiralis, M. cf. spinulosus, Mon. ex gr.
vomerina
Collection at 86.9 m (285 ft), sakmaricus-laqueus Zone: M. spiralis, M. priodon, 2B. sp., Mon. ex gr.
vomerina
. innotatus cf. obesus, C. normalis, G. sp.
. normalis, C. innotatus cf. obesus
153
Collection at 88.4 m (290 ft), sakmaricus-laqueus Zone: M. cf. praecedens, M. spiralis, M. cf.
spinulosus, Ct. sakmaricus, Ct. aff. lapworthi, Ret. geinitzianus angustidens, St. grandis grandis
Collection at 89.9 m (295 ft), sakmaricus-laqueus Zone: M. priodon, Mon. ex gr. vomerina, Ct. cf.
sakmaricus, Ct. aff. lapworthi, St. grandis grandis, Ret. geinitzianus angustidens
Collection at 93 m (305 ft), sakmaricus-laqueus Zone: M. priodon, Pr. cf. dubius, Ct. aff. lapworthi, Ct.
aff. rigidus
LOCALITY 12B_ Clearwater Creek, same section as 12A, but sampled on the east side of the creek. Not
measured, but collected in stratigraphic succession.
Collection 1F, acuminatus Zone?: C. miserabilis
Collection 2F, acuminatus Zone: C. miserabilis, C. cf. rectangularis, G. sp., 2D. ex gr. modestus
Collection 3F, acuminatus Zone: C. innotatus innotatus, G. sp.
Collection 4F, spiralis Zone: M. spiralis, M. priodon, Mon. cf. crenulata, St. cf. grandis imperfectus
Collection 5F, spiralis Zone: M. spiralis, M. priodon, M. sp., Mon. ex gr. vomerina, Ret. geinitzianus
angustidens
Collection 6F, sakmaricus-laqueus Zone: M. spiralis, M. priodon, Mon. cf. crenulata, Ct. cf. sakmaricus
LOCALITY 13 Beaver River, Yukon, southern Mackenzie Mountains, a single collection: approxi-
mately 60°30'N, 125°58’W.
spiralis Zone: M. spiralis, M. cf. priodon, Mon. vomerina gracilis, Mon. cf. griestoniensis, St. grandis
imperfectus
154
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ISSN 0384-8159
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