Age of Wainwright Skulls Report
Archives Department · PRELIMINARY REPORT ON THE AGE OF THE WAINWRIGHT CRANIAL SPECIMENS
RESTRICTED INTERNAL CIRCULATION ONLY
TRANSCRIPT OF ORIGINAL REPORT
Filed 12 Dec 1893
Prepared by Dr. Beatrice Holloway, Assistant Keeper of Zoological Records
____
MATERIAL EXAMINED
Twenty-four avian skulls recovered by P. H. Wainwright from an inland limestone chamber in Mauritius have been received and entered into the Society collection.
All twenty-four conform in their principal features to the known remains of Raphus cucullatus. The breadth of the cranium, depth and curvature of the beak, position of the orbit, and articulation of the lower jaw leave no reasonable doubt as to the identification.
The question before the Department is therefore not what animal the skulls represent, but when those animals lived.
The commonly accepted account places the extinction of the dodo in the latter part of the seventeenth century, with 1690 generally treated as the latest credible limit. The Wainwright specimens are not consistent with that date.
CONDITION OF THE BONE
The skulls vary considerably in surface condition but remain remarkably uniform in their degree of preservation.
- None is fully fossilized.
The bone is stained by soil and mineral water, yet remains light, porous, and readily distinguishable from the older subfossil dodo material held in European collections. The internal surfaces of several specimens are unusually clean. Fine structures within the nasal passages remain intact, as do thin portions of the palate that commonly perish under prolonged burial.
In six specimens, the cranial sutures remain sharply defined.
Two retain dark fibrous material along the lower margin of the beak. This material has not yet been positively identified, but its position is consistent with remnants of the keratinous sheath or attached connective tissue.
Specimen WE-0a-09 retains a small quantity of dried matter within the rear of the cranial cavity. Further examination has been suspended pending determination of whether analysis would require damage to the specimen.
The Department finds it highly improbable that such material could have survived in its present state since the seventeenth century under the conditions described.
SEDIMENT AND DEPOSITION
Red volcanic soil adheres to every skull examined.
Within the cavities of the bone is a pale limestone dust identical to that collected from the floor and lower walls of the chamber. Fine roots pass through or around several specimens, but the degree of penetration is limited. The largest roots cross above the skull layer rather than through it.
The skulls appear to have been deposited before the growth of the present root mat but after the accumulation of the lowest limestone wash.
The layer containing the skulls had subsequently been covered by leaf mould, loose stone, and material introduced through openings in the roof. It had not remained wholly sealed from air or moisture.
This circumstance explains the staining and partial mineralization of the outer surfaces. It does not explain the preservation of the more delicate internal structures if the deposit is assumed to be two centuries old.
ASSOCIATED PLANT MATERIAL
Plant matter recovered immediately beneath and between the skulls includes leaf fragments, seed husks, root fibres, and several pieces of cut or crushed cane.
Dr. Holloway has identified one seed husk as belonging to a cultivated variety not recorded in the district before the closing years of the eighteenth century. A second identification remains uncertain but may represent a plant introduced through plantation cultivation during the first decades of the present century.
The cane material bears signs of cutting rather than natural breakage.
It is therefore probable that human activity occurred within or near the chamber after the establishment of plantation agriculture in the surrounding region.
ASSOCIATED HUMAN OBJECT
A fragment of white clay tobacco pipe was recovered beneath the edge of Specimen WE-0a-17.
The fragment was embedded in the same compacted soil as the lower surface of the skull and was covered by the same continuous mineral crust. It does not appear to have entered the deposit from above. The stem bears part of a maker’s impression. Comparison with commercial records indicates that the mark was used by a London manufacturer between approximately 1806 and 1822.
The pipe fragment cannot establish the precise date of the skull.
It does establish that the layer in which both objects rested was disturbed, formed, or remained open during the early nineteenth century.
LOCAL TESTIMONY
The statement of Étienne Marot, taken by Wainwright on 11 June 1893, records that large forest birds survived in the region during Marot’s childhood.
Marot further states that he ate the meat of such a bird at a family wedding when he was approximately nine or ten years of age. His account would place the event between 1824 and 1827.
Testimony of this kind cannot be accepted as scientific proof. It is nevertheless notable that Marot’s description of the bird, the use of the bones, and the location of the deposit led Wainwright to the correct limestone formation before the skull chamber was discovered.
His account therefore possesses a degree of independent corroboration that cannot be dismissed.
ASSESSMENT
No single observation presented above is sufficient to date the Wainwright skulls with certainty.
Bone may survive unexpectedly. Sediment may be disturbed. Plant matter may be carried downward by roots or water. Human objects may enter older deposits through later activity. Memory may alter over time.
The difficulty is that every line of evidence points in the same direction.
- The condition of the bone is too recent.
- The plant material is too recent.
- The associated pipe fragment is too recent.
- The local testimony describes living birds too recently.
To preserve the accepted extinction date, it would be necessary to assume that the skulls survived for two centuries in an exceptional state, that later material entered the layer without visibly disturbing it, that the pipe fragment came to rest beneath one skull by chance, and that Marot’s family history independently invented a bird matching both the recovered remains and the location of the chamber.
The Department does not consider that combination credible.
PRELIMINARY CONCLUSION
The Wainwright skulls are the remains of dodos that lived during the early nineteenth century.
On present evidence, the most probable date of death lies between 1806 and 1830.
This conclusion extends the survival of Raphus cucullatus by more than one hundred years beyond the date generally accepted by naturalists.
It does not establish when the species finally became extinct.
No claim should be made that the Wainwright population represented the last surviving birds on Mauritius. The chamber has not been fully excavated, the eastern opening has not been traced to the surface, and the surrounding forest has not been adequately surveyed.
The absence of later remains must not be interpreted as evidence that later birds did not exist.
Recommendation: All public disclosure is to be withheld. The exact location of the chamber is to remain restricted. A second survey should be undertaken before further disturbance, with particular attention to nesting material, unexplored passages, and any sign of more recent occupation.
A fourth, lying inland beyond the cultivated districts and west of the principal uplands, corresponds closely with the material detail Crowther recorded.
THIS DEPARTMENT DOES NOT CLAIM that the precise deposit can be identified from the drawings alone. It does believe the search area can now be reduced from the whole of Mauritius to a narrow belt of inland limestone country, much of it imperfectly surveyed.
A field investigation is therefore recommended.
The appointed naturalist should carry copies of Folios 112–126, with particular attention to Crowther’s notes concerning soil, limestone residue, root penetration, and the sequence in which the specimens were delivered. The object of the inquiry should be to locate the original bone deposit, recover additional material if present, and determine whether Crowther’s unnamed bird represents an unknown species or an incomplete example of one already described.
A general survey of cave fauna and inland deposits should provide sufficient explanation for the work.
Recommendation: Proceed with a limited expedition during the next suitable field season.
ARCHIVE NOTE, added 7 January 1893:
Recommendation approved. P. H. Wainwright appointed to the inquiry. Relevant folios released under supervised copy.