Afri<:an Study Monographs, Supplementary Issue 2: 45-56, March I 984
FOSSILIFEROUS LOCALITIES OF THE NACHOLA-SAMBURU HILLS AREA, NORTHERN KENYA
Martin PICKFORD
National Museums of Kenya Hidemi ISHIDA
Yoshihiko NAKANO
Faculty ofHuman Sciences, Osaka UniJiersity Hideo NAKAYA
Faculty of Science, Kyoto Unil'ersity
ABSTRACT In the four geographic/stratigraphic areas of the Samburu Hills and Nachola. west
of Baragoi, Kenya. a significant number of fossiliferous localities was found. Nachola area is dated
to the middle Miocene, the Namurungule Formation in Samburu Hills to the upper l'vliocenc,
Kongia area to the Mio-Piiocene and Holocene to the area near Suguta Valley and in the drainage
systems of the Samburu Hills to the Holocene. The site BG X in Nachola yielded a number of
fossils provisionally assigned to Kenyapitlzecus. An important large hominoid specimen occurred in
Site SH ~~ of the Namurungule Fonnation. Undoubtedly a great many additional sites await
discovery.
INTRODUCTION
Fossils were known to occur in a few places bet ween Baragoi and the Suguta Valley many years
ago, but little systematic study was undertaken until 1980. Previous to this, fossil wood was
collected at Emuruilem (Site BG W) by amateurs (Baker. 1963 ). In !980, the Japan-Kenya Expedition, under direction of one of the authors (H.!.), started
prospecting west of Baragoi and located a number of fossiliferous areas near Nachola (Ishida eta/.,
1981 ). During 198~ an extended Held season was spent in the region and a significant number of
important sites was found ranging in age from middl~ Miocene to llolocene.
This report is to place on record basic informaiion concerning localities discovered during the
1982 field season. The basic data includes the position of each site plotted on aerial photographs;
the stratigraphic position of each site, and details of taxa collected therefrom, together \Vith the
total number of fossils found in each site.
Fossils recovered during 1982 occur in four basic geographic/stratigraphic areas. Middle tvliocene
fossils occur in sedimentary intercalations in a volcanic sequence in the Nachola area 10-15 krn
west of Baragoi (Figs. 1-3). Upper Miocene fossils occur in the Namurungule Formation Samburu
Hills 27-32 km west of Baragoi (Figs. I, 4-6). Mio·Pliocene fossils occur in the Kongia area a few
kilometres north of the Namurungule Formation, while Holocene fossils are found in grey silts near
the Suguta Valley and in travertine and terrace deposits in the drainage systems of the Samburu
Hills (Figs. 8, 9). Undoubtedly a great many additional sites await discovery.
J5
( 1' -._I I I h I~ I IF I /I I I ~I 1-'f.~l I I I I r' n ~ /l I I ( I) ~r-1 IJ \ J rl I \ I I,_ __ lf I 1---1' Ill ..__/ r L :=::::t ) \ •• :::7'-'1', -!d ( \j I~ ,L 1 r / V11m: f{ I I 1- k ( I '( 1 I ~(I ~~ I J-4 I I ( I ~ II I !,__/ I I I
/~I 1 I I 1 I I NACHOLA fl I~ I I ( f I~J·u \ I II' ~I F1 J 111 ~{ I I r';-/ 1'--\ I 'Y'I"'~J{ I ~\, I I I I I"Y I l?l I I jl I I UI"KI 'rr ~I l"'ll~~ I~ " ,/ ~
I ,---1 1 11~1 I .~ <--:':- I \--) I r.-- I I ..-I , I I I ~~1aj_l_ 1\1~' I I I I 1/ KONG lA r- AVENA ATURKON ~·
!'-~ I I DJ I lc I ~ y---1 I ;1--' l1 I. 1\1\;! 1/ -L I _4---~-~-J 1711' 1/1 1--K 1; 1::r I I
00
1\~ I"!"\ 1~1 I.J t I 1-- .. ( I I II I Nl I \ I fiH \{'(1\ ~ )i )~ardg;;;-. r . )1 I I I I I \ v (\JJ---T' I I r,.J I I I ll I\ J \ ,---YI I~ I~'"] \._. l'lP lA-\
r--1 /I I J fll I -r---l \ I 1\ U/"" -L,I_, r--; I~ I ''\i\Lf) 1/ ll "-I I ~ 1/ I ·\ ?/ ,_.,. /I I I } VI~ \~ \J-"TI rl I (I l'r-
--,_1 NAMURUNGULE I~ II kf~-n (,Y' I? I "-- 11 /h.J/1; t-/ \1 ~-'· N ·~I !I) 1 }---- r--:s ~ -1 ~~ I u 1 (--. I r A)\..L.___ ,_~ , x I'· 1 I \ /
vi hi I L'"~·~ dt I j 1\ I q-' I u I I I ~ [\ 11 .f ')I I_/( 'h I I I \.~- ,....-c.i""" .._
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~ I I h ~ i ~ \,\ I I ,(" +=" ( I lr~~"'. h I I T"·J ! I l/ I l)\ I I~ II I I I ~NAKAPORATELAOO
I I 1,1 I ~-. I I ;!, II 1'11 I "I 1'~1 'I I (I\ : l\_1 I I I I I\ I I ;1 1"',1 [
~ ~
n :r, ., 0 ::0
0 _tl
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I tl ( I / l'lJ I I I ;I~ I~ I~Y~ I I) I JJ I k! _Jf11t-h· I I .-! II . I) I r (f I I I" 1~1 1i ~ h~ I lr+-'~ ~ /1\ I"'\ I I 'I
0 ?"' :<
/"'~ I I I ~ I( I !I W---'- I .I If\. I I I y I I\ I l I \--_ JO 50 40 0 1 2 3 4 5
z ~ :r, ~
Km z 0 ., ;:I 0.
:r: z ~ :r,
Fig. I. Location Map: Baragoi-Samburu Hills ~ -< >
Fossiliferous localities J7
The Nacho/a Area (Fig. 2)
Fossil sites have already been reported in this area (Ishida eta! .. 1982; Baker, 1963 ). Mammals
tend to be rare in the sediments of the Nachola area, but crocodile and turtle remains are abundant
at some sites. Fossil wood is also common at certain levels in the Emuruilem ,\!ember. The most
'. -. ;,.~-·~.;, ..
. .... . ..:;~. . . .~-" ~{i" ~
~ ~ . ' j"-;(;"'
"+ ·-4 .)
Fig. 2. Nachola Sheet
J8 M. PICKFORD, II. ISHIDA, Y. NAKANO and H. NAKA YA
important site found in this area during 198~. was the Site BG X, which yielded a number of
fossils provisionally assigned to Kenyapithecus, plus a few other mammals. Figure 3 summarises
the collections from the Nachola Sites. It should be noted that fossils occur in sediments at various
levels in the succession. The lowermost deposits occur below the volcanic sequence at the eastern
edge of the volcanic field. Above this is a series of phonolitic and basaltic lavas with intercalated
tuffs and sediments which yield abundant fossil wood and rarer mammals. The upper part of the
Nachola sequence is comprised of a thick sequence of basaltic lavas.
TAXON
SITE
u v w X
ClJ c
~ VI ~E~ "0 ::J • ~ "0 'iii u ClJ ::J ·-
c ::J ~ ClJ .J: ·~ 0 ClJ ~ ..... :.= "0 - a.- ClJ '- c "0 c-
•n :;:::; X "' ·a.- C 0 .J: ClJ "0 •- C C VI ...... >- .., .J: ..... u ·- - E ClJO E c- o.oo- ::J c u u c 0 VI >- 0 E c c - 0' .E E VI 0 .~ - ClJ c E ·- ·- 0 0 0 ·- '- '- ClJ > ClJ 0 ClJ .J: .~ '- ::J a..ut-a..~::s::::tf)<!>Oa::<!>t-O::~
• •
• •
•
•••••••••••• • •
Fig. 3. Distribution of fauna- Nachola
The Sam bum Hills Area (Figs. 4 and 5)
VI
VI VI 0 --0
>---c 0 ::J
0
75 38 3
73
The uppermost Member of the Aka Aiteputh Formation, comprises palaeosols. weathered
basalts and siliceous limestones, and minor fluvial sediment lenses. It is generally poorly fossilerous
but has yielded molluscs and mammals (Figs. 4, 5 and 6). Baker ( 1963) provides a brief description of the Namurugule strata, which he included in his
Tirr Tirr Series. The strata arc, however. stratigraphically well below the Tirr Tirr Formation which
has been dated at 3.8 m.y. (Baker eta!., 1971 ). Uncomforably below the flat lying Tirr Tirr Alkali
Rhyolite occurs a westward dipping sequence of Nagubarat and Kongia Basalts with intercalated
sediments. best exposed in the Kongia area (Fig. 8). Unconformably below these lavas occurs the
Namumngulc Formation which is Upper Miocene in age. A large number of sites is now known in
Fossiliferous localities JQ
Fig. 4. Namurungule Sheet
the Namurungule Formation (Figs. 4 - 6). but most of them yield rather scrappy fragments of bone and teeth. Aquatic faunal elements arc frequently found, but terrestrial fossils occur in many of the sites. Probably the most interesting and important site found in 1982 is Site SH 22 which
yielded an important hominoid specimen plus a moderately diverse vertebrate fauna. Hipparion and bovids occur at many sites while giraffids are rarer. Deinotherium and Tetralophodon are
moderately well represented in the collections. while most other mammalian taxa are rare. Fossil fish. turtles and crocodiles are ubiquitous. Gastropods are. however. notable by their absense.
50 M. PICKFORD. H. IS III DA, Y. NAKANO and H. NA.KA YA
Fig. 5. Nakaporatelado Sheet
Two intriguing sites yielding impressions of leaves. feathers and foot prints were found (Fig. I 0).
The well-bedded facies common over much of the Namurungule area may well contain many more such sites.
Fossiliferous localities
TAXON
LOCALITY
1 4 5 6* 7 8 9
10 11 12 13 14 15 16 17• 18 19 20 21 22 23 24 25 26 27 28 29 30 31. 32 33 34 35 36 37 38 39 40 41 42 43 44 45. 46. 49
111 011 111 c -.c 111111 c
41 ~Eg .g~ 2::J
c -o c c -o ::J -o ·- ·.:: ., E '0 c ·u; '0 .. .. 0 ·- 0 c 0 ell 0 c ell ell o -::J-c 'O~~~~~~c~-co ~ :::-o~-oo .-oell~ 0111 -ouO-o'Oe~~ 0 Ill '0 .. u ·- ell 0 ~ :5 0 > u 0 ·;:: c ~ ·- :.:: 0 ~ ell 0 E >- c '0 .!: ~ 0 0 ·- 0 .~ c N c ::: ::J '0 - u u o c o ·- "' E u c ~ !: c- ~ c >- c 01·-1/l Ill 0 - 0 ~ ~ ell >- ·- - ·- c ~ 0 c ~ c > c ·- ~ ell ·.:: c ~ > 0 ~ ell 111 0 ~ ~ ·- >- 111 ·- ~ 0 ~~U~~>O<IOO~U~UIZ~~~m
•
• •••• ••••
• • • • • • •
• • • • • •
• • • • • • • • • •
• • • • • •••• • • • • • • • • •••• • • • • •••• • • • • • • • • • • • • • • • • • • • • •••• • • •
• • • • ••••
•
• • •
•
•
•
•
•
• • • •
• •
• • •
• • • • •
• • •
• •
• • • •
• • • •
• • •
•
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•
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• • • • • ••••
• • • • •
• • • • • • • • • • • • • •
• • • • •
• • •
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• • • • • • • • • • • • • •
•
•
0111 >-'iii - Ill• :=o CIJ.. 0 ::J
0
38 161 43 10 29
142 67 2
51 107 30 46 22 24 26 6 1
38 32
166 24 22 28 28 67 19 1
37 9
11 4
42 1
26 18 13 1 1 4 1 5
16 1 2 1
Fig. 6. Distribution of Fauna- Namurungulc (*Aka Aiteputh Formation)
51
52
1- CARNIVORE 2 -RUMINANT J- RHINOCEROTIDAE 4-UNKNOWN 5-BIRD
M. PICKFORD, H. ISHIDA, Y. NAKANO and H. NAKAYA
Bedding plane with footprints
01
0
Metre
Fig. 7. Footprints at Site 32
Fossiliferous localities 53
Fig. 8. Kongia Sheet
111e Kongia Area (Fig. 8)
Six to seven kilometres north of the 1\amurungule Formation is a thick succession of basaltic
lavas. In a few places thin sedimentary intercalations are known to occur between lava tlows
(Fig. 8). A very preliminary survey made in 1982 indicated the palaeontological potential of this
sequence, which unconformably overlies the Namurungule Formation. Two richly fossiliferous
5J l\L PICKFORD. H. ISHIDA. Y. NAKANO and H. NAKAYA
Fig. 9. Ayena Aturkon Sheet
sites were found, both of which yielded abundant Mollusca, but few vertebrates. However. one of
the sites (SH 47) yielded 1/ippopotamus. fish and a varanid. The hippo is particularly interesting as
it is the earliest local record of this group. The older Namurungule sites, although clearly aquatic in
their depositional environments. have not yet yielded Hippopotamus. This finding is in accord
with currently available infonnation concerning hippopotamid origins and distribution (Pickford.
1983) which suggests that the earliest known Hippopotamus occurrences in Kenya are about 7
f.'ossilifcrous localities 55
million years old. Prior to this time, hippopotamids were represented by Kenyaporamus, the genus
which occurs at Namurungule. A separate report on the Kongia Mollusca has been prepared (Pickford, 1984 ).
l
D
D
D D
Grey silts, travertine --~-- Sites GB 1-10
Ti rr Tirr Fmn
Nagubarat Fmn
Kongia Fmn~.-- ~-- .. ------i----SH 47-48
.!! ~- 10-16, 18.19, Shale\ brown conglomerate-S,---~ --4, 5. · .25.29, 32,33,35-38,
2 e 28. 39. "'41. 42. Mudf low :I u.
E SH 1, 7-9,20-24,28,27,30, Shale------------·----~- i--- 34,40.43,44.49,
limestone- - - -
Basalt
.J: ... :I Q. I) c: ... E < u.
· SH6. 17, 31, 45, 48,
Fig. 10. Stratigraphic Positions of fossil sites: Sam":JUru Hills
Holocene Sites Holocene sediments occur in the Suguta Valley as well as in the present day drainage feeding
into the valley. High level terrace deposits occur extensively in the Samburu Hills. These presuma
bly accumulated during a period when the Suguta Valley was filled with water. The resemblance of
the grey silt facies to the Galana Boi Foml<llion, which occurs further north in the East Turkana
area, is marked.
5o M. PICKFORD. H. ISHWA, Y. NAKANO and H. NAKA YA
In some areas higher than the highest lake terraces, occur river terraces and travertine deposits. The latter frequently contain fossil leaves and molluscs. A separate report (Pickford, 1984) discusses the distribution of Molluscs in the Holocene sediments.
In the vicinity of Baragoi Township is a series of fluviatile deposits which contains subfossil snails and vertebrates (Site G B I I).
The value of the Holocene deposits lies in the information they impart about conditions in the Samburu area in the recent past. The Baragoi site contains molluscs usually found in conditions much colder than those prevailing at Baragoi today. The Suguta Valley, when full of water would undoubtedly have had a marked effect on the local climate. The travertine deposits indicate the former existence of lime charged water seepages in an area which is now virtually waterless.
ACKNOWLEDGEMENTS We acknowledge the help of the following organizations and individuals:
The Japanese Ministry of Education, Science and Culture, The Kenyan National Council of Science and Technology. The Office of the President of the Kenya Government. Administrators of the Samburu District, Mr. Richard E. F. Leakey, Director Chief Executive of the National Museums of Kenya.
REFERENCES
Baker, B.H .. I 963. Geology of the Baragoi Area. Rept. Ceo/. Sun·. Kenya 53: 1-74. Baker, B.H., L. Williams, J. Miller and F. Fitch, 1971. Sequence and Geochronology of the Kenya
Rift Volcanics. Tectunophysics II: 191-215. Ishida. II., S. Ishida, M. Torii, T. l'vlatsuda, Y. Kawamura and K. Koizumi, 1982. Report of Field
Survey in Kirimun, Kenya. 1980. Study of the Tertiary Hominoids and their PalaeoenPironmelllS in East Africa l: 1-181, Osaka Univ. Osaka, Japan.
Pickford, M .. 1983. On the origins of J-lippopotamidae together with descriptions of two new species, a new genus and a new subfamity from the Miocene of Kenya. Geobios, 16: 193-2 l 7.
Pickford M., 1984. Fossil Mollusca from the Samburu Hills. Northern Kenya. African Study i\/onographs. Supplementary Issue No.2: 141-145.