Bulletin of the Geological Survey of Japan, vol. 70 (1/2), p. 225–247, 2019

Notes and Comments

A report of Permian, Triassic, and Jurassic radiolarian occurrences from the Ashio
terrane in the Hachioji Hills, eastern Gunma Prefecture, central Japan
Tsuyoshi Ito1,*
Tsuyoshi Ito (2019) A report of Permian, Triassic, and Jurassic radiolarian occurrences from the Ashio
terrane in the Hachioji Hills, eastern Gunma Prefecture, central Japan. Bull. Geol. Surv. Japan, vol. 70 (1/2),
p. 225–247, 7 figs, 1 table, 6 plates.
Abstract: The Ashio terrane, which is a Jurassic accretionary complex, is exposed in the Hachioji Hills,
eastern Gunma Prefecture, central Japan. The Ashio terrane in the Hachioji Hills mainly comprises chertand muddy mixed rock with siliceous mudstone and sandstone. Early Permian (Sakmarian, Cisuralian),
Late Triassic (Carnian–Norian), and Jurassic radiolarians occurred in the chert, whereas Middle Jurassic(Bajocian–Bathonian) radiolarians occurred in the siliceous mudstone.
Keywords: radiolaria, Permian, Triassic, Jurassic, Ashio terrane, Hachioji Hills, Kiryu, Ohta, Gunma
Prefecture, Japan

1. Introduction
Mid-Mesozoic accretionary complexes, including theTamba–Mino–Ashio and Chichibu composite terranes,
are exposed in central Japan (e.g. Matsuoka et al, 1998;
Nakae, 2000) (Fig. 1). The Ashio terrane is distributed
over the Ashio Mountains and its adjacent regions. Many
researchers have reported the presence of several fossil
types, such as selachoid, brachiopod, fusulinid, conodont,
radiolarian, and ammonoid, from the terrane (e.g. Yabe,
1903; Morikawa and Horiguchi, 1956; Hayashi, 1963;
Aono, 1985; Kamata, 1996; Muto et al., 2018).
The Hachioji Hills in the eastern Gunma Prefecture are
geographically separated from the Ashio Mountains. The
Ashio terrane is exposed on the northeastern side of thehills. As aforementioned, numerous fossil occurrences
have been reported from the Ashio Mountains. Suzuki(1898a, b) first noted the presence of radiolarian remains
within the siliceous rocks found within the Ashio
Copper Mine of the Ashio Mountains. Since the 1960s,
radiolarians and conodonts have been extracted from the
Ashio terrane in the Ashio Mountains. However, despite
numerous fossil occurrences in the Ashio Mountains, only
a few brief reports have been written about the Ashio
terrane in the Hachioji Hills. Masuda (1989) reported on
the discovery of Middle Jurassic radiolarians from chertand manganese nodules within mudstone. Meanwhile,
Hayashi et al. (1990) reported some possibly Triassic
radiolarians from chert.
1*

The author obtained Permian, Triassic, and Jurassic
radiolarian assemblages from the Ashio terrane in the
Hachioji Hills. This article aims to briefly report thegeology of the Ashio terrane in the Hachioji Hills withthe radiolarian occurrences.

2. Brief research history of the Ashio terranein the Ashio Mountains
Several researchers have investigated the Ashio terranein the Ashio Mountains, and some geologic maps ofthe mountains have been presented (e.g. Harada, 1886;
Kawada and Ozawa, 1955; Yoshida, 1956, 1957; Watanabe
et al., 1957; Fujimoto, 1961; Hatori, 1965; Yanagimoto,
1973; Igo et al., 1976; Aono, 1985; Sato and Aono, 1985;
Kamata, 1996). However, a few geologic maps have
depicted the area of the mountains comprehensively(Hayashi and Hasegawa, 1981; Sudo et al., 1991) because
the Ashio Mountains they are distributed over a broad
area surrounding both the Gunma and Tochigi prefectures.
Figure 2 displays a simplified geologic map of the Ashio
Mountains. Major previous studies with their geologicaldivisions are summarized in Fig. 3.
The Ashio terrane had been considered a member of
the Chichibu Paleozoic strata until the 1970s. AlthoughHayashi (1963, 1964, 1968a, b, 1971) discovered Triassic
conodonts from the“Chichibu Paleozoic strata,” heconsidered the possibility that the Triassic-type conodonts
had appeared in the Permian. Koike et al. (1970, 1971,

AIST, Geological Survey of Japan, Institute of Geology and Geoinformation
Corresponding author: T. Ito, Central 7,1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan. Email:− 225 −

@aist.go.jp

Bulletin of the Geological Survey of Japan, vol. 70 (1/2), 2019

Fig. 1 Index map of the study area with distribution of mid-Mesozoic accretionary complexes
in Kanto District, central Japan (based on Matsuoka et al., 1998; Nakae, 2000).

1974) and Conodont Research Group (1972, 1974)
similarly pondered whether or not the“Chichibu Paleozoic
strata”contains Triassic strata based on the discovery of
the Triassic conodonts. Hayashi and Hasegawa (1981)
showed the geologic maps of the Ashio terrane in the
Ashio Mountains and estimated their age to be Permianto Triassic.
From the viewpoint of an accretionary complex geology
based on the plate tectonics, Aono (1985) surveyed the
Ashio terrane in the southeast Ashio Mountains andobtained Triassic conodonts as well as Triassic andJurassic radiolarians. Kamata (1996) later investigateda wide area of the south–southwest Ashio Mountains
and defined three tectonostratigraphic units, namely the
Omama, Kurohone–Kiryu, and Kuzu complexes. The
former two complexes are characterized by mixed facies
including some kind of blocks, such as chert, limestone,
and sandstone. The Omama Complex contains large
amounts of basalt and limestone, whereas the Kurohone–
Kiryu Complex contains small amounts of such rocks.
The Kuzu Complex is characterized by coherent facies,
composed mainly of repeated chert-clastic sequences withbasaltic-limestone blocks. Kamata (1997) subdivided theKuzu Complex into three units.

3. Geologic outline of the Hachioji Hills
In the Hachioji Hills, the Ashio terrane is exposed in thenortheastern side of the hills (Fig. 4). The Ashio terranein the Hachioji Hills consists mainly of chert and muddy
mixed rock with siliceous mudstone and sandstone.
The chert is mostly gray, dark-gray, and bright-grayin color (Fig. 5A). Red chert, which yielded Permian
radiolarians, is observed at only one outcrop (Fig. 5B).
The chert is generally well-bedded (bed thickness:
3–10 cm) (Figs. 5A, 5B) and is composed mainly ofsiliceous microfossils (possibly radiolarian remains) andcryptocrystalline quartz with a few clay minerals (Fig.
6A).
The siliceous mudstone is dark-gray (Fig. 5C) andweakly-bedded (bed thickness: 3–10 cm). Most siliceous
mudstone occurs within the muddy mixed rock (Fig. 5D).
The siliceous mudstone comprises scattered microfossils(possibly radiolarian remains) with clay materials (Fig.
6B).
The sandstone is medium to fine-grained, gray or
brown lithic arenite (Fig. 6C). The sandstone is generally
included within muddy mixed rocks as blocks.
The muddy mixed rock comprises a dark-gray mudstone− 226 −

Radiolarians from the Hachioji Hills, Gunma Pref (Ito)Fig. 2 Simplified geologic map of the Ashio Mountains (modified after from Sudo et al., 1991;
Geological Survey of Japan, AIST, 2018). Geographical names in brackets indicate
1:50,000 topographic maps published by Geospatial Information Authority of Japan.

Fig. 3 Stratigraphy of the Ashio terrane in the Ashio Mountains in the major previous studies.
Stratigraphic divisions in levels of the formations are omitted. Gr.: Group. Carb.:
Carboniferous.

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Bulletin of the Geological Survey of Japan, vol. 70 (1/2), 2019

Fig. 4 Geologic map of the Ashio terrane in the Hachioji Hills. The Paleogene is based on Takahashi and Yanagisawa (2003).

matrix with blocks of chert, siliceous mudstone, andsandstone (Figs. 5D, 5E, 5F). The size of the blocks ofeach rock is as follows: the chert blocks range from several
meters to more than 100 m (Fig. 4); the siliceous mudstone
blocks, a few micrometers (Fig. 6D) to several meters(Fig. 5C); the sandstone blocks, several centimeters (Fig.
5E) to a few meters (Fig. 5F).
On the southwestern side of the hills, the Paleogene
covers the Ashio terrane. According to Takahashi
and Yanagisawa (2003), the Kanayama Welded Tuff

unconformably overlies the Ashio terrane; the Yabuzuka
Formation unconformably overlies the Kanayama Welded
Tuff and the Ashio terrane. The Kanayama Welded Tuffand the Yabuzuka Formation can correlate to the Paleocene
and the lower Miocene, respectively (Takahashi et al.,
1991; Takahashi and Yanagisawa, 2003; Nomura et al.,2017). The unconformity boundaries between the Ashio
terrane and the Yabuzuka Formation are observable near
the Momiyama Pass.

− 228 −

Radiolarians from the Hachioji Hills, Gunma Pref (Ito)Fig. 5 Field occurrences. A: Triassic gray bedded chert in a quarry of Meisei Kousan Co. Ltd.;
B: Permian red bedded chert along a forest road; C: Jurassic siliceous mudstone along
a forest road; D: Muddy mixed rock including small siliceous mudstone blocks in aquarry of Meisei Kousan Co. Ltd.; E: Muddy mixed rock including sandstone blockin a quarry of Meisei Kousan Co. Ltd.; F: Muddy mixed rock and sandstone block in
a quarry of Meisei Kousan Co. Ltd.

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Bulletin of the Geological Survey of Japan, vol. 70 (1/2), 2019

Fig. 6 Photomicrographs of thin sections. A: Lower Jurassic dark-gray bedded chert; B: Dark
gray siliceous mudstone; C: Sandstone included in muddy mixed rock; D: Muddy mixedrock including siliceous mudstone fragment.

4. Radiolarian occurrences andage assignments
4. 1 Materials and methods
A total of 46 samples of chert and siliceous mudstone
were collected from the Ashio terrane in the Hachioji
Hills. The samples were crushed into ca. 1 cm fragments
and were then soaked in a hydrofluoric acid (HF) solution(ca. 5%) at ca. 20°
C–25°
C room temperature for 24hours. Residues, which were collected through a sievewith a mesh diameter of 0.054 mm, were enclosed withina slide prepared with a photocrosslinkable mounting
medium (GJ-4006, Gluelabo Ltd.). These slides wereobserved using a transmitted light microscope and were
photographed. Among the samples, 16 samples yieldedradiolarians (Table 1).
4. 2 Permian radiolarians from chert
Two chert samples yielded Permian radiolarians (Plates
1, 2). Spicules were also discovered from both samples.
Samples IT16071006 and IT16071005 yielded abundant

Pseudoalbaillella sakmarensis. This species occurs in
the Pseudoalbaillella lomentaria Assemblage Zone andlower Pseudoalbaillella rhombothoracata Assemblage
Zone (Ishiga, 1986). Although characteristic species of
the Pseudoalbaillella rhombothoracata Assemblage Zone
(i.e. Pseudoalbaillella rhombothoracata) have neverbeen found from the both samples, Pseudoalbaillella
scalprata Holdsworth and Jones and Pseudoalbaillellapostscalprata Ishiga, the ancestors of Pseudoalbaillellarhombothoracata Ishiga (Ishiga, 1983), were obtained
from the both samples and either sample, respectively.
Consequently, both samples can be correlated to the upper
Pseudoalbaillella lomentaria Assemblage Zone (middle
Cisuralian, lower Permian).
4. 3 Triassic radiolarians from chert
Triassic radiolarians were obtained from eight chert
samples (Plates 3, 4). Among these samples, one sample(IT16071201) yielded an age-undeterminable conodont
fragment and one sample (IT16072301) yielded certain
sponge spicules.

− 230 −

Radiolarians from the Hachioji Hills, Gunma Pref (Ito)Pseudoalbaillella lomentaria Ishiga and Imoto
Pseudoalbaillella scalprata Holdsworth and Jones
Pseudoalbaillella postscalprata Ishiga
Pseudoalbaillella sp.
Polyfistula sp.
arm of Quadriremis gracilis (De Wever and Caridroit)
Entactinia sp.
Latentifistula texana Nazarov and Ormiston
Latentifistula sp.
Quadriremis sp.
Pseudotormentus kamigoriensis De Wever and Caridroit
Pseudotormentus sp.
Quadricaulis inflata (Sashida and Tonishi)

Conodont fragment
Sponge spicule

IT16071207

IT16120505
chert

sl. md. IT16071001

sl. md. IT16120104

IT16112604
chert

+

IT16071206

IT16112602
chert

+

chert

IT16072301
chert

+

chert

IT16071405

IT16071402
chert

Pseudoalbaillella sakmarensis (Kozur)

IT16071404

IT16071401
chert

+
+

chert

IT16071201
chert

+
+

IT16071403

IT16071006
chert

+

Spumellaria gen. et sp. indet.
Nassellaria gen. et sp. indet.
Closed-end Nassellaria
Striatojaponocapsa synconexa O’Dogherty, Goričan andDumitrica
Praeparvicingula sp.
Dictyomitrella ? kamoensis Mizutani and Kido
Minocapsa sp.
Hsuum ? matsuokai Isozaki and Matsuda
Zhamoidellum sp.
Spinosicapsa sp.
Pantanellium sp.
Paronaella sp.
Protunuma sp.
Parahsuum sp.
Eucytidiellum sp.
spine B5 of Sugiyama (1997)
spine A2 of Sugiyama (1997)
spine D1 of Sugiyama (1997)
spine D2 of Sugiyama (1997)
spine C of Sugiyama (1997)
spine of Capuchnosphaera sp.
Pseudostylosphaera japonica (Nakaseko and Nishimura)Pseudostylosphaera longispinosa Kozur and Mostler
Pseudostylosphaera sp.
Tritortis kretaensis (Kozur and Krahl)
Tritortis sp.
Mesosaturnalis octospinus Sugiyama
Mesosaturnalis sp.
Praehexasaturnalis tenuispinosus (Kozur and Mostler)
Muelleritortis sp.
Capnodoce sp.
Hozmadia sp.
Triassocampe sp.
Sarla sp.

chert

IT16071005

Lithology

chert

Sample no.

chert

Table 1 Fossil occurrences from the Ashio terrane in the Hachioji Hills. sl. md.: siliceous mudstone.

+

+

+
+

+
+

+
+

+
?

?
+
?

+
+
?

?
+
?

?
+
+
+
+
+
+

+
+
?
+

?

+
+
+

+

+
?
+
?
cf.
?

?

?
?

?
+
+
+

?
+
?
+
+
+

?
?

+
cf.
+
+
+
+
+
?
+
?
?
+
+
+

+

+

− 231 −+++

Bulletin of the Geological Survey of Japan, vol. 70 (1/2), 2019

Sample IT16071201 yielded some type of spines
shown by Sugiyama (1997). According to the range ofthe radiolarian zonation displayed by Sugiyama (1997),
spines B5, D1, and D2 co-occur in TR6A–TR6B. Spine A2
occurs in the TR3A–TR6A. Based on the co-occurrence,
it is possible that the sample corresponds to TR6A,
uppermost Carnian–lowermost Norian, Upper Triassic.
From sample IT16071401, some satunalids wereobserved. The Family Satunalidae appeared in the Carnianand occurs abundantly in the Upper Triassic (e.g. De
Wever et al., 2001). Therefore, the sample tentatively
corresponds to the Upper Triassic.
Sample IT16071402 yielded satunalids appearing topossess six spines, identified as Praehexasaturnalis cf.
tenuispinosus (Kozur and Mostler). The Praehexasaturnalis
tenuispinosus group occurs in TR7–JR0A, middle Norian–lower Hettanginian, Upper Triassic–lowermost Jurassic(Sugiyama, 1997).
Samples IT16071403 and IT16112602 yielded
Pseudostylosphaera japonica (Nakaseko and Nishimura).
The Pseudostylosphaera japonica group occurs in theTR2B–TR5A, middle Anisian–lower Carnian, Middle–
Upper Triassic (Sugiyama, 1997).
Sample IT16071404 yielded spines C and D1 of
Sugiyama (1997). The former and latter occur in TR4B–
TR5A and TR5A–TR7, respectively (Sugiyama, 1997).
The co-occurrence range of these two types is restricted
in TR5A, Carnian.
Sample IT16071405 yielded Mesosaturnalis octospinus
Sugiyama. The occurrence range of this species isrestricted in TR7–TR8A, middle Norian.
Sample IT16072301 yielded spines of Capuchnosphaera?
sp. Capuchnosphaera occurs in the Carnian–lower Norian(O’
Dogherty et al., 2009b).
Sample IT16112604 yielded Tritortis kretaensis(Kozur and Krahl). This species occurs in TR4A–TR5A,
upper Ladinian–lower Carnian, Middle–Upper Triassic(Sugiyama, 1997).
4. 4 Jurassic radiolarians from chert
Three chert samples yielded possibly Jurassic
radiolarians (Plate 5). However, fossil preservation is
generally poor and hence the detailed ages are uncertain.
All samples yielded closed-end Nassellaria. This type ofNassellaria appeared in the Early Jurassic (O’Dogherty etal., 2009a). Sample IT16071206 yielded Parahsuum sp.
The occurrence range of this genus is the Hattanginian–
Kimmeridgian, Jurassic (O’Dogherty et al., 2009a). Hereit is tentatively considered that all samples are Jurassic,
although the occurrence range closed-end Nassellaria
reaches the Cretaceous (O’Dogherty et al., 2009a).
4. 5 Jurassic radiolarians from siliceous mudstone
Two siliceous mudstone samples yielded Middle
Jurassic radiolarians (Plate 6).
Sample IT16071001 yielded Striatojaponocapsa
synconexa O’
Dogherty, Goričan and Dumitrica. These

species abundantly occur in the upper Striatojaponocapsa
plicarum zone and lower Striatojaponocapsa conexa
zone (Hatakeda et al., 2007), Bajocian–lower Bathonian(Matsuoka, 1995).
One specimen of closed-end Nassellaria (Plate 6.39)
from sample IT16120104 resembles to Tricolocapsa cf.
rüsti Tan Sin Hok sensu Yao (1979). This specimen cooccurred with Striatojaponocapsa plicarum. Here, it istentatively considered that the sample is correlated with
the Striatojaponocapsa plicarum zone.

5. Implication
In this study, Permian, Triassic, and Jurassic radiolarians
were discovered from the chert and Jurassic radiolarians
were obtained from the siliceous mudstone. Previously,
Masuda (1989) reported Eucyrtidiellum unumaense(Yao) and Unuma echinatus Ichikawa and Yao fromthe chert of the Hachioji Hills. According to Matsuoka(1995), Eucyrtidiellum unumaense occurs mainly in theStriatojaponocapsa plicarum zone to Striatojaponocapsa
conexa zone, Bajocian–lower Callovian. Unuma
echinatus occurred Laxtorum? jurassicum zone to
Striatojaponocapsa conexa zone, Aalenian–Bathonian(Matsuoka and Yao, 1986). Masuda (1989) stated thata similar radiolarian assemblage was obtained from themanganese nodule within the mudstone, although theirimages were not shown.
Combined with this previous study, the primary ocean
plate stratigraphy of the Ashio terrane in the Hachioji
Hills is summarized below. The chert contains Sakmarian(Cisuralian, Permian), Carnian–Norian (Upper Triassic),
parts of the Anisian–Ladinian, possibly Early Jurassic,
and Bajocian–lower Bathonian (Middle Jurassic) (Fig. 7).
Furthermore, the siliceous mudstone and the manganese
nodule within the mudstone contain Bajocian–lower
Bathonian (Middle Jurassic).
Acknowledgement
This study is based on part of the ongoing study ofthe quadrangle series, 1:50,000“Geology of the Kiryu
and Ashikaga,”conducted by the Geological Survey ofJapan, AIST. The author is grateful to Meisei Kousan
Co. Ltd. for giving the permission to research on thecompany’s property. Comments given by a reviewer,
Takayuki Uchino (Geological Survey of Japan, AIST),
have improved greatly this manuscript.

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*Translated by the author.
Recieved May 9, 2018
Accepted January 18, 2019群馬県東部八王子丘陵の足尾テレーンから産出したペルム紀，三畳紀及びジュラ紀放散虫の報告
伊藤

剛

要 旨
群馬県東部の八王子丘陵にはジュラ紀付加体足尾テレーンが露出する．この足尾テレーンは，チャートと泥質混在岩を主体とし，珪質泥岩，泥岩，砂岩を伴う．ペルム紀前期（シスウラリアン世サクマーリアン期），後期三畳紀（カーニアン期～ノーリアン期）及びジュラ紀の放散虫化石がチャートから産出し，中期ジュラ紀（バッジョシアン期～バトニアン期）放散虫が珪質泥岩から産出した．

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Plate 1		 Permian radiolarians and spicules from chert.
		 1–6, 21–24: Pseudoalbaillella sakmarensis (Kozur)
		 7, 8: Pseudoalbaillella scalprata Holdsworth and Jones		 9, 10, 19, 30, 34, 41: Latentifistula spp.
		11–14: Latentifistula texana Nazarov and Ormiston		 15, 29, 35, 36, 40, 46: Sponge spicule		 16–18, 31–33, 37, 39, 43, 45: Pseudotormentus spp.
		 20, 44: Quadricaulis sp.
		25: Pseudoalbaillella sp.
		 26–28: Entactinia? sp.
		38: Polyfistula sp.
		42: Quadricaulis inflata (Sashida and Tonishi)− 236 −

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Plate 2		 Permian radiolarians and spicules from chert.
		 1–7, 26–36: Pseudoalbaillella sakmarensis (Kozur)
		8: Pseudoalbaillella scalprata Holdsworth and Jones		9: Pseudoalbaillella postscalprata Ishiga
		10: Entactinia? sp.
		 11, 13: Latentifistula texana Nazarov and Ormiston		 12, 22, 41: Pseudotormentus kamigoriensis De Wever and Caridroit
		14: Quadricaulis sp.
		 15, 16, 47, 48: arm of Quadriremis gracilis (De Wever and Caridroit)		 17: arm of Quadricaulis inflata (Sashida and Tonishi)
		 18–21, 23–25, 45: Latentifistula? spp.
		37: Pseudoalbaillella cf. lomentaria Ishiga and Imoto
		 38, 39: Pseudoalbaillella sp.
		40: Entactinia? sp.
		42–44: Quadriremis? spp.
		 46: Polyfistula sp.

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Plate 3		 Triassic radiolarians and conodont fragments from chert.
		 1: Spine B5 of Sugiyama (1997)
		 2: Spine A2 of Sugiyama (1997)
		 3, 4, 28, 30, 31, 33: Spine D1 of Sugiyama (1997)
		 5: Spine D2 of Sugiyama (1997)
		 6: Pseudostylosphaera? sp.
		 7, 9, 17, 20, 21, 23, 29, 51, 54–57: Spumellaria gen. et sp. indet.
		 8: Conodont fragment
		 10–16: Mesosaturnalis? sp.
		 18, 19, 22, 38: Nassellaria gen. et sp. indet.
		24: Capnodoce? sp.
		25–27: Praehexasaturnalis cf. tenuispinosus (Kozur and Mostler)
		 32: spine C of Sugiyama (1997)		34–37: Triassocampe? spp.
		39–43: Pseudostylosphaera japonica (Nakaseko and Nishimura)		 44–46: Pseudostylosphaera sp.
		 47, 48: Pseudostylosphaera? spp.
		49: Muelleritortis sp.
		 50, 52, 53: Capnodoce? spp.

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Plate 4		 Triassic radiolarians and sponge spicules from chert.
		 1–3, 5–10: Mesosaturnalis octospinus Sugiyama
		 4, 14–16: Spumellaria gen. et sp. indet.
		11: Capnodoce? sp.
		12: Hozmadia? sp.
		13: Tritortis? sp.
		17: Spine of Capuchnosphaera? sp.
		18–21: Triassocampe? sp.
		22: Sarla? sp.
		 23–26: Pseudostylosphaera japonica (Nakaseko and Nishimura)		27: Pseudostylosphaera sp.
		28–30: Pseudostylosphaera longispinosa Kozur and Mostler		 31, 32: sponge spicules		 33: spicule
		34: Tritortis kretaensis (Kozur and Krahl)− 242 −

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Plate 5		Jurassic radiolarians from chert.
		 1–9, 12–19, 32–37, 39, 41–44, 50: Closed-end Nassellaria
		20: Protunuma? sp.
		 10, 11, 21, 22, 26, 28–30, 38, 45, 48, 51, 58, 59: Nassellaria gen. et sp. indet.
		 23, 24: Hsuum? matsuokai Isozaki and Matsuda
		25: Parahsuum sp.
		27: Parahsuum? sp.
		 31, 46, 57: Spumellaria gen. et sp. indet.
		40: Eucytidiellum sp.
		47: Pantanellium? sp.
		49: Spinosicapsa? sp.
		 52–56: Praeparvicingula? sp.
		 60: Pantanellium sp.
		 61: Paronaella? sp.

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Plate 6		 Jurassic radiolarians from siliceous mudstone.
		 1, 2, 4–6: Stichocapsa? sp.
		 3, 51: Nassellaria gen. et sp. indet.
		7: Striatojaponocapsa synconexa O’Dogherty, Goričan and Dumitrica
		 8, 14: Gongylothorax siphonofer Dumitrica		32: Eucytidiellum sp.
		 9–13, 15, 17–31, 33, 39, 41–44, 47: Closed-end Nassellaria
		 16, 34–38: Nassellaria gen. et sp. indet.
		 40, 45, 46: Minocapsa? spp.
		48: Dictyomitrella? kamoensis Mizutani and Kido
		 49, 50, 52: Praeparvicingula? spp.

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