The Piltdown Mandible and Cranium
M. F. Ashley Montague
American Journal of Physical Anthropology 1951
[464] In June 1951, I enjoyed the opportunity of examining the original human remains from Piltdown (Piltdown I and II) together with the undescribed remains of two other skulls and a right second lower molar tooth recovered by Charles Dawson at Barcombe Mills, near Piltdown. The Barcombe Mills remains form the subject of a separate communication. In the present paper I wish to present certain observations and the conclusions drawn from them as a consequence of my recent study of the Piltdown remains.
An examination of Piltdown skulls I and II together with the mandible attributed to Piltdown I at once reveals a striking disparity. This does not appear to have been sufficiently emphasized. This disparity is presented by the fact that while the cranial bones of Piltdown I and II are extraordinarily thick the mandible is comparatively remarkably thin, the latter being of about the same general thickness as that of the average mature female chimpanzee. This is, surely, a highly significant point, one which has been quite insufficiently [465] ??? , for in no known skull of any of the anthropomorpha, extinct or extant, indeed in no known primate, does there exist a disparity of this kind between the thickness of the cranial bones and the thickness of the mandible. When the cranial bones are thick the mandible is also thick and massive; when the cranial bones are moderately developed in thickness so is the mandible. Indeed, in the moderately thick-skulled gorilla the mandible is massive, while among the moderately thick-skulled australopithecines the thickness and massiveness of the mandible may be, as in A. crassidens, simply enormous. On such morphological grounds, therefore, it would seem highly improbable that the gracile mandible found with the Piltdown cranium bones belonged to the same individual.
This is, of course, not the first time that attention has been drawn to the lack of morphological congruity between mandible and cranium. More than 20 years ago Hrdlicka ('30) wrote:
"The handling of the original bone impressed one once more with the great difference that exists between the study of a cast however well made and that of the original. It is very probable that some of the statements made about the jaw and the teeth and some of the conclusions arrived at by some authors, would not have been made had they been able to study the jaw itself.
"The first strong impression which the specimen conveys is that of normality, shapeliness and relative gracility of build rather than massiveness. When, after studying the specimen for a good part of two days, the observer took in hand the thick Piltdown skull, there was a strong feeling of incongruity and lack of relationship, and that feeling only grew on further study. As a rule there exists a marked correlation between the massivity of the skull–particularly if as in this case the upper facial parts were involved in the same–and the lower jaw. A finely chiselled mandible of medium or sub-medium strength belongs as a rule to a skull that is characterized in the same way, and vice versa.. To connect the shapely, wholly normal Piltdown jaw with the gross, heavy Piltdown skull into the same individual seems very difficult. After prolonged handling of both the jaw and the skull there remained in the writer a strong impression that the two may not belong together, or if they do the case is totally exceptional."
This is precisely the strong impression which a handling of the actual bones made upon me.
Were the mandible of the same degree of massiveness as the cranial bones, its other anthropoid features would be easier to reconcile with the hominid cranial bones, but as it is the disharmony in substance between mandible and cranial bones is so striking it becomes highly improbable that they could have belonged to the same creature. Cer[466]tainly in the primates the rule is that the mandible is more massive than the cranial bones. If the Piltdown mandible belonged to the Piltdown cranial bones it would in this respect be unique. In the course of my studies I have examined well over 10,000 human and other primate crania, and I have never seen anything approaching the disharmony in massiveness between mandible and cranium which exists in the case of the Piltdown remains. Pathological and genetic disorders affecting the mandible (micrognathia) alone do occur, but they are extremely rare and, in any event, in no way resemble the condition seen in the Piltdown jaw. The Piltdown jaw is in every way a perfectly normal one. Occasionally one may see a mandible which seems rather small for the cranium to which it undoubtedly belongs, as for example, in Skhul II, but even this is extremely rare and is a very different thing from the disharmony which exists between the Piltdown mandible and cranium. Variability being what it is, it is not impossible that the mandible may belong with the cranium, but the disharmony in massiveness alone, not the mention the numerous other features, renders it high improbable that the mandible belonged to the same creature as disported the Piltdown cranium.
It has often been argued that together the numerous other anthropoid features of the mandible, both quantitatively and qualitatively, so far outweigh the hominid features that the mandible must be considered as belonging to a separate creature, to an anthropoid ape. The cranial bones are those of a man; the mandible is that of an ape. Surely the balance of the arguments is in favor of this conclusion? The fact that the bones were recovered from the same vicinity (though not together and at an interval of several years), that they are stained the same dark brown color, 1 and that they are contemporary does not constitute evidence that they belong to a single creature. 2
"The results of the fluorine test," writes Oakley ('50) "have considerably increased the probability that the mandible and cranium represent a single creature. The relatively late date indicated by the summary of evidence suggests moreover that 'Piltdown Man,' far from being an early primitive type, may have been a late specialized hominid which evolved in comparative isolation. In this case the [467] peculiarities of the mandible and the excessive thickness of the cranium might well be interpreted as secondary or gerontic developments."
Oakley undertook the determination of the fluorine content of the Piltdown fossils in order to resolve the question of their probably age. It had been claimed by some students that the mandible was Villafrancian while the cranium was of later age. Oakley's tests resolved this point and demonstrated that mandible and cranium were of the same age. And this is what Oakley means when he declares that the probability is increased that "mandible and cranium represent a single creature." In such a context this is indeed so; but in point of fact what is demonstrated is not that the bones belong to the same creature but that they are of the same age.
As far as the peculiarities of the mandible and the excessive thickness of the cranium being secondary or gerontic developments, it is quite unnecessary to account for the thick cranial bones by "secondary or gerontic developments," since in all known Lower, Middle, and early Upper Pleistocene men, with the possible exception of Rhodesian man, the cranial bones as well as the mandible are comparatively thick.
Broom ('50) has recently stated that he "now has scarcely any doubt that the Piltdown mandible belongs to the same individual as the associated brain-case. He considers that Eoanthropus was a big-brained type of man which evolved on a quite different line from Homo. The 'simian shelf' in the lower jaw is probably not an indication of close affinity with the anthropoids, but a specialization due to evolution parallel with that of the modern apes, just as the large brain of this type of man may have been a parallel development to what is found in the Homo line."
This is all quite possible but, it seems to be, quite improbable. The cranial capacity of Piltdown man is estimated at about 1,348 cm.3 [468] Such capacities are by no means rare in the third interglacial, as witness the Neanderthal types, and even earlier, as is shown by the second interglacial (Mindel-Riss) Swanscombe skull with an estimated cranial capacity of 1,350 cm3, and the lower Upper Pleistocene Tayacian Fontéchevade skull with an estimated cranial capacity of 1,470 cm3. There seems to be no good reason why Piltdown man could not have inherited his cranial capacity from the same general source and in the same manner as Swanscombe, Fontéchevade, and Neanderthal–not to mention other types. It certainly does not appear to b necessary to introduce the deus ex machina of parallel evolution to explain the presence of a modern-size brain of so late a representative of Homo sapiens as Piltdown man. Except for the thickness of the bones Piltdown man is essentially a sapiens type. This fact, taken together with the thick bones and the large brain, makes the anthropoid mandible all the less likely to belong with the cranium.
The simian shelf is characteristic of the great apes. It is not found in any form of fossil ape-man or man. The probabilities of its ever developing in a hominid jaw, particularly one which went with a sapiens cranium, seem to me extremely low.
One of the arguments which has carried great weight in the Piltdown controversy has been the statement that there is no evidence that anthropoid apes and other non-hominid primates ever existed in Britain. If true this would be a telling point, but the fact is that it is not quite true. Dr. Kenneth Oakley has drawn my attention to the fact that as long ago as 1854 Owen ('45) described and figured the fragments of a right maxilla with M2 in situ, from the brick earth series at Grays Thurrock in Essex, and over 40 years ago Hinton ('08) described the distal end of a humerus of another macaque, not unlike Macacus inuus, from the Norfolk Forest Bed. The Grays deposit is generally accepted as Middle Pleistocene. The Forest Bed is widely held to be Lower Pleistocene. A macaque is not an anthropoid ape, but the presence of such a catarrhine primate in Pleistocene England increases the probability of an anthropoid ape having lived and survived in the forests of England right into the Pleistocene. Fossil macaques from the Upper Villafranchian (Schreuder, '45) and Miocene apes are well known on the continent of Europe, and in regions as close to England as France. The coast of France is a matr of 21 miles from the coast of England at the present time, and at the narrowest part the English Channel is now barely 100 feet deep as Flint ('47) points out, this must have been replaced by an isthmus during the lowered sea levels of the glacial ages. The presence of the fossil remains of such southern (warm-climate) types as Elephas meridionalis, Hippopotamus, lion, and hyena strongly suggests that during certain interglacial periods [469] there was a land connection between England and France. The geological evidence renders it even more probable that such land conditions existed at various times during the Tertiary, and it is a possible hypothesis that during this period the anthropoid ancestors of the owner of the Piltdown mandible originally migrated into England. However, until the remains of such forms have actually been discovered in England this argument must remain but a speculation. What is not a speculation is that the Piltdown mandible is morphologically disharmonic with the cranium, and that non-human catarrhine primates have been discovered in Lower and Middle Pleistocene deposits in England, a fact which increases the probability of the ??? existence of anthropoid apes in that country.
It is submitted that these are points which are worthy of more than they have thus far received.
I have to thank the Keeper of the Department of Geology (Natural History), Mr. G. N. Edwards, and Dr. Kenneth P. Oakley of the same Department for permission to examine the Piltdown remains. I am also indebted to Dr. Oakley, and to Mr. J. T. Robinson of Pretoria, South Africa, for much stimulating discussion, without which the present paper would probably not have come into being. I am indebted to Professor Hallam L. Movius, Jr., for drawing my attention to Schreuder's paper.
Summary
The difference in massiveness between the Piltdown mandible and the Piltdown cranial bones being so great, it is suggested that on these grounds alone the mandible most probably does not belong with the cranium. Together with the great number of other anthropoid traits characterizing the mandible, it is suggested that the disharmony between the latter and the cranium is too great for these to belong to a single individual.
The argument that no primates other than man have ever been found in England is shown to be unfounded, since the remains of two Pleistocene macaques have been discovered in England and described by Owen in 1845 and by Hinton in 1908.
The presence of fossil macaques and anthropoids in France and of probable land connections during the Tertiary, and as late as the Pleistocene, make very real the possibility of the migration of such forms into England. Hence, the occurrence of the mandible of an anthropoid in the same vicinity and contemporaneously with that of a fossil man as late as the Middle Pleistocene, and possibly the third interglacial, is a possibility somewhat less remarkable than has hitherto appeared.
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1 Due to the fact that Dawson soaked the bones in a solution of bichromate of potash. Wee Woodward ('33).
2 The fluorine test has shown that the mandible and the cranial bones are of the same age. Oakley and Hoskins ('50) found that all the available bones from the region of Piltdown which were of undoubted Lower Pleistocene (Villafranchian) age contained 2-3% fluorine, while all those of known later date showed less than 1.6% fluorine. The Piltdown mandible, the cranial fragments, and the isolated canine tooth, as well as the remains of the second skull found two miles away in 1915, showed very little fluorine (average 0.2%). The Piltdown skull remains are therefore not of Lower Pleistocene age, but belong to a considerably later period. Oakley has provisionally referred them to the last interglacial (Russ-Würm) period ('50), while admitting the possibility that they may belong to the second interglacial (Mindel-Riss).
It requires to be emphasized that the fluorine method does not provide absolute geological dating. In the particular instance of the Piltdown remains it has provided clear evidence that this material constitutes one of the latest elements in the gravel, which contains a mixed assemblage. Naturally one now looks to the geological evidence to see how late the final accumulation of the gravel can be. It has been pointed out that the associated contemporary fauna indicates temperate woodland conditions (Hopwood, '35), i.e., interglacial (since the gravel in the terrace indicates that it is Pleistocene), for the terrace is little more than 60 feet above the present river, and according to physiographers this most probably belongs to the last interglacial, but could conceivably represent a phase of channelling in the second interglacial.
Literature cited
Broom, R. 1950 Summary of a note on the Piltdown skulls. Adv. Sci., 6:344.
Flint, R. R. 1947 Glacial Geology and the Pleistocene Epoch. John Wiley, New York
Hinton, M.A.C. 1908 Note on the discovery of a monkey in the Norfolk 'Forest Bed.' Geol.
Mag., n.s., dec. V, 5:440-444.
Hopwood, A. T. 1935 Fossil elephants and man. Proc. Geol. Assn., 46:46-50.
Hrdlicka, A. 1950 The Skeletal Remains of Early Man. Smithsonian Miscellaneous Collections,
83:79.
Oakley, K. P. 1950 Relative dating of the Piltdown skull. Adv. Sci., 6:343-344.
Owen, R. 1845 Note sur le découverted, faite en Angleterre, de restes fossiles d'un quadrumanane du genre Macaque, dans une formation d'eau douce appartenant au niveau pliocène.
C. R. Acad. Sci., 21:573-575. Figured as Macacus pliocenus, Owen, 1846, British Fossil Mammals and Birds, xlv.
Woodward, A. S. 1933 Early Man and the Associated Faunas of the Old World. Science, 78:89.