DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.49270#0157
84
H. F. Mathews
on digging sticks have also been found.1 In addition to these objects, James Scott of the
Nigerian Tin Corporation has made a very interesting find consisting of a considerable
number of roughly spherical stones. These were found in a layer of gravel situated on
the side of the Ninkada valley, at a depth of six feet under the present surface. The
stones, which are about the size of a cricket ball, have been submitted to Henry Balfour,
Curator of the Pitt Rivers Museum at Oxford, who states that some of them show distinct
signs of having been used as if for grinding and pounding. Whether they are wholly
artificial, or have been ground to a spherical form in potholes and then improved and
adapted by human agency, it is difficult to determine.
The problem of the age of these spheres is made very difficult by the topsy-turvy state
of the geology. The gravels in which they are found, at first glance, resemble river
terraces (known in mining parlance as “bench-gravels”) because of their position along
the valley sides. But the terrace gravels rest on a layer of material which appears water
worn, while above these gravels is a stratum which shows no sign of having been transported
either by water or by wind. This order is exactly the reverse of what would occur in the
case of true river terraces. Smellis, of the Glasgow University Geological Department,
to whom Scott submitted the samples of material for microscopical examination, suggests
that the layer immediately under the gravel represents the old ground surface. He thinks
that the gravel may have been brought down by a sudden rush of water (cf. the deposition
of material by sudden flood in the wadys of the Egyptian desert). The layer above the
gravel which shows no evidence of transportation, may be material that is being brought
down by solifaction (i. e. the downward creep of closely packed detritus in regions of
great diurnal variation in temperature). Scott believes this to be the true history of the
deposit, since the hills behind are granite with pegmatite veins, which is the kind of
formation Smellis postulates as the parent of the layer above the gravel. Moreover the
whole of the lower ground toward the river is a micaceous schist area, such as Smellis
requires for the source of the layer below the gravel.
The present moment affords a great opportunity for the fuller investigation of these
questions as there are two mining companies still working in this and neighboring valleys,
and it is through their excavations that the implements mentioned above have come to light.
In the same deposit there was also found a small stone, roughly resembling the head
of a snake. Balfour believes that this is a natural resemblance improved by human
agency. A natural flaw, caused by the more rapid weathering of a soft layer in the stone,
seems to have been enlarged artificially to represent the mouth.
1 Such digging-weights are well known in the Anglo-Egyptian Sudan. They are still employed among the Bush-
man, cf. W. H. I. Bleek and L. C. Lloyd, Specimens of Bushman folklore, London, 1911, photograph facing p. 326.
Ed.].
H. F. Mathews
on digging sticks have also been found.1 In addition to these objects, James Scott of the
Nigerian Tin Corporation has made a very interesting find consisting of a considerable
number of roughly spherical stones. These were found in a layer of gravel situated on
the side of the Ninkada valley, at a depth of six feet under the present surface. The
stones, which are about the size of a cricket ball, have been submitted to Henry Balfour,
Curator of the Pitt Rivers Museum at Oxford, who states that some of them show distinct
signs of having been used as if for grinding and pounding. Whether they are wholly
artificial, or have been ground to a spherical form in potholes and then improved and
adapted by human agency, it is difficult to determine.
The problem of the age of these spheres is made very difficult by the topsy-turvy state
of the geology. The gravels in which they are found, at first glance, resemble river
terraces (known in mining parlance as “bench-gravels”) because of their position along
the valley sides. But the terrace gravels rest on a layer of material which appears water
worn, while above these gravels is a stratum which shows no sign of having been transported
either by water or by wind. This order is exactly the reverse of what would occur in the
case of true river terraces. Smellis, of the Glasgow University Geological Department,
to whom Scott submitted the samples of material for microscopical examination, suggests
that the layer immediately under the gravel represents the old ground surface. He thinks
that the gravel may have been brought down by a sudden rush of water (cf. the deposition
of material by sudden flood in the wadys of the Egyptian desert). The layer above the
gravel which shows no evidence of transportation, may be material that is being brought
down by solifaction (i. e. the downward creep of closely packed detritus in regions of
great diurnal variation in temperature). Scott believes this to be the true history of the
deposit, since the hills behind are granite with pegmatite veins, which is the kind of
formation Smellis postulates as the parent of the layer above the gravel. Moreover the
whole of the lower ground toward the river is a micaceous schist area, such as Smellis
requires for the source of the layer below the gravel.
The present moment affords a great opportunity for the fuller investigation of these
questions as there are two mining companies still working in this and neighboring valleys,
and it is through their excavations that the implements mentioned above have come to light.
In the same deposit there was also found a small stone, roughly resembling the head
of a snake. Balfour believes that this is a natural resemblance improved by human
agency. A natural flaw, caused by the more rapid weathering of a soft layer in the stone,
seems to have been enlarged artificially to represent the mouth.
1 Such digging-weights are well known in the Anglo-Egyptian Sudan. They are still employed among the Bush-
man, cf. W. H. I. Bleek and L. C. Lloyd, Specimens of Bushman folklore, London, 1911, photograph facing p. 326.
Ed.].