Art. XI.—Notice of the Earnscleugh Cave.
[Read before the Otago Institute, 14th September, 1874.]
During the course of last summer I twice visited this cave, accompanied on both occasions by Dr. A. T. Thomson, and although it has already been very well described by Dr. Thomson himself (Trans. N.Z. Inst., IV., p. 111), by the Hon. Captain Fraser (ibid, V., p. 102), and by Mr. Cockburn Hood (ibid, VI., p. 387), the importance of the subject will, I hope, be a sufficient excuse for my bringing it under your notice once more.
The rocks of the district are mica-schist, dipping 10° S.S.E., and the cave in question appears to have been formed by a gentle slipping of a portion of the rocks towards the valley of the Conroy, the dip not having been altered by the slip. The cave itself is very irregular in outline, but always narrow, and quite different in character from the ordinary caves found in limestone countries. At the furthest point that can be reached the cave communicates with the surface by means of a small opening in the roof, and it is continued still further on by a fissure too narrow to get into. This surface opening at the end, as well as the lateral opening mentioned by Captain Fraser, ensure thorough ventilation to the whole of the cave. The
inclination of the cave is rather steep, averaging perhaps 1. in 3 from the entrance to the extremity. The floor is filled to a considerable depth with fine micaceous sand, derived from the decomposition of the mica-schist rocks in the district, and it appears to be gradually filling up.
It is only in the upper part of the cave, near the entrance, and in the talus formed at the entrance by the debris fallen from above, that remains of Dinornis and Cnemiornis have been found, while the extremity of the cave contained a considerable number of bones of a duck, * belonging apparently to an extinct genus, together with its nests and eggs, and also a few bones of parrots, hawks, and other small birds which have not yet been examined. With these were also remains of rats, the tuatara (Sphenodon punctatum), and fragments of the egg-shell of the Moa and the jaw of a pleurodont lizard. A few of the wing bones of the duck still retain portions of skin and feathers attached to them, and many of both wing and leg bones are gnawed half through by rats. A portion of the skin of a rat was also found, but without any hair on it. This rat's skin, as well as the wing of the duck with skin attached was found under several inches of sand, and indeed I am not aware that any were found on the surface of the floor. In fact, the whole of these bones were mixed together in such a way as to lead to the conclusion that the rat and the duck were contemporaneous.
It may, I think, be taken as certain that the rocks on either side of the cave have not moved since the bones were deposited in it, and I quite agree with Dr. Thomson and Mr. Hood that the cave was never inhabited either by man or by the Moa. The ducks, however, must have lived in it, as they built their nests and laid their eggs there, and probably rats and the tuatara lived with them. I also agree with Captain Fraser that no storm water could have washed the Moa remains into the cave, and think that Mr. Hood's suggestion that the birds fell in accidentally and were unable to extricate themselves is the only possible explanation of the facts. The bones of the parrots and smaller birds may perhaps have been taken in by the rats.
I have already remarked that the cave is gradually filling up, owing to its steep inclination, and the fact that it is not yet filled up shows that its origin cannot date back for a very long period of time. The fact of the rats having gnawed the bones of the ducks shows that they were omnivorous, and therefore probably the brown rat (Mus decumanus), but it may be possible to determine this from the remains that they have left behind them, which are not, however, very numerous. The brown rat may have been introduced into this province by the whalers in the early part of this century, but it certainly
[Footnote] * This duck is about the size of Anas superciliosa. It has heavy legs, comparatively small wings, but with a well-developed keel to its sternum, and a remarkably short bill. The egg is ovoid and measures 2.6 inches in length by 1.75 inches in breadth.
could not have existed here previous to that. The remains of the rat appeared to me to be mixed up pell-mell with those of the duck, but as the surface of the floor had been disturbed by previous explorers the appearance may have been deceptive.
Whether the remains of Cnemiornis and the Moa are contemporaneous or not with those of the duck there is no direct evidence to show, as each are found at opposite ends of the cave; but as many of the Moa bones were found in the talus at the entrance of the cave, and others on the surface of the floor, there is no reason for supposing that they are older than those of the duck, while the bones of both appear to have lost an equal amount of organic matter. The Moa bones mentioned by Mr. Hood as occurring above those of the duck must, I think, have been moved down into that part of the cave by visitors. I never saw any in that position myself, although they occur abundantly in the upper part of the cave, and may, therefore, in one sense be said to lie above those of the duck, which are found only in the inner or lower part of the cave.
None of the Moa remains are marked by rats' teeth, and the only reason that I can offer in explanation of this is, that the fleshy remains of the Moa may have been covered up with sand.
In order to ascertain whether there was any special quality in the earth of the cave which would assist in preserving the skin and flesh of animals, Professor Black has kindly had analysed for me some of the micaceous sand from the floor of the cave, and a fragment of incrustation from the side, with the following results:—
The incrustation is simply a mixture of quartz-sand and carbonate of lime, containing particles of earthy matter and small fragments of mica-schist. The earth from the floor of the cave was a mixture of pulverised mica-schist (potash mica), fragments of bone, dry powdered clay, quartz-sand, fragments of the stems of plants, and portions of carbonate of lime. No soluble salt was found in the earth, except phosphates, derived no doubt from the bones. Professor Black adds, “I do not know of anything in the specimens analysed to account for the preservation of the organic matter of the Moa remains accompanying them. In this case there does not appear to have been an incrustation over the remains, and I am not aware that the remains have been petrified by the substitution of calcareous and siliceous matter for the original substance.
On the whole, I am inclined to think, notwithstanding the fact that at least three of the birds found in the cave belong to genera now extinct, that the weight of the evidence goes to show that these remains are not very old, and that probably they do not date further back than the commencement of the present century.
I may also mention that during the autumn the cave has been carefully cleared out by Mr. Martin for the Museum Committee, and that the whole of
the bones that he obtained have been deposited in the Otago Museum, together with all the more valuable Moa remains from the cave, which have been most liberally presented by Dr. A. T. Thomson.
Notes on the Anatomy of the Moa Remains found at Earnscleugh Cave, Alexandra. By Millen Coughtrey.
(To accompany Captain Hutton's Notes.)
The remains with which I am specially called upon to deal are—a, Moa's neck and skin; b, right femur and muscles; c, left fibula; d, left tibio-tarsus.
(a) Moa's Neck.
An excellent description of this specimen is given by Dr. Hector in the Trans. N.Z. Inst. Vol. IV., p. 115, to which I wish to add a few notes.
In that paper, fig. a, pl. 5, exhibits clearly the general characters and the form of the portion of the integument preserved.
The conical papillæ of the dermis vary in size and the distances of their approximations to one another.
Those on the dorsal and upper aspect of the neck, allowing for the wrinkling of the skin, are much closer together and smaller in size than those of the ventral surface and lower part of the specimen; the upper ones being 0.15 to 0.10 inches apart, the lower and ventral ones 0.2 inches apart.
Allowing for the due and consequent contraction of the skin from age and drying, we must regard the Moa as having possessed not a very thick coat of feathers.
The bifurcate calamus, showing the secondary after-shaft in the Moa's feathers, as depicted in fig. 2, pl. 5, loc. cit., is very well seen in all the feathers of ventral surface of preparation, but this character is not so common to those of dorsal surface.
The soft parts still attached to the six cervical vertebræ are respectively—
Portions of the supra and inter-spinous ligaments of four lower cervical vertebræ. *
Intervertebral ligaments and cartilages for the central and zygapophysial joints. Anterior common and capsular ligaments well seen.
The left moiety of deep cervical fascia.
On the outer surface of this fascia, and on the under surface of the skin, also in the interspaces between and around the transverse processes, are the remains of vascular tissue.
So far as it is possible to make out the following are the muscular attachments still remaining:—
[Footnote] * This is almost identical with Dr. Hector's description, plus the names of the parts left.
(a) Serratus Magnus Anticus.
That slip of this muscle in the struthious bird which is the homologue of Levator anguli scapulæ in flying birds.
Origin of digitation from the under surface of left transverse process of last cervical.
The four lowest between the spines five lowest cervical vertebræ.
(c) Longus Colli (Anticus).
The running origin of this muscle as it arises from the hypapophysial processes of the last two cervical vertebræ but one.
The other parts are indistinguishable.
The small bone (size 0.4 by 0.2 inch), mentioned by Dr. Hector as articulating with the first dorsal vertebra, but of which the fig. in pl. 5 is very misleading, * is of great morphological interest. For the under and posterior aspect of the tip of the transverse process of the first dorsal vertebra on both sides, presents a depression into which the above little bone and its companion of the opposite side would fit; and the opposing surfaces respectively of the depression and small bone present the characters of united osseous surfaces that in course of development would become joined together.
From the above reasons, and from the fact that it is in the dorsal region of the column where epiphyses of the transverse processes prevail, I would regard the above small bone as the epiphysial element of the left transverse process of the first dorsal vertebra.
The surface of this bone at present adhering to a tag of the deep cervical fascia is that with which the tubercular portion of the rib would articulate.
Epiphyses of the transverse processes are very rare in creatures below mammalia.
A strong tuft is left attached to a marked rough prominence 3 inches below the epitrochanterian ridge, well on the outer side of base of great trochanter, also 1.6 inches from the sharp margin which separates the pre-from the post-trochanterian ridge.
At this tuberosity the outermost limb of commencement of the rough striæ leading down to the ectocondylar fossa begins, the other limb commencing in a depression on the post-trochanteric region into which Quadratus femoris is inserted.
From the anterior margin of this same depression a sharply defined line
[Footnote] * This is not the bone mentioned by Dr. Hector, as that bone, Dr. Hector informs me, has been lost.—F. W. H.
runs directly down the outer surface of shaft of bone, and fades gradually on the posterior aspect of ectocondylar tuberosity.
Glutœus medius and Glutœus quartus.
The remains of these two muscles seem to me to be present in some muscular fibres still attached to the ectotrochanterian tuberosity and part of the depression behind this.
Glutœus quintus (Mayer).
On a plane below, but intermediate to the tuberosity to which Glutœus externus is attached, and the ectotrochanteric tuberosity, is a small depression of about one-third of an inch wide, and into it is inserted a slender tuft of tendon, which I take to belong to the above muscle.
The ectotrochanteric surface is divided into two portions by a well marked ridge curving from the posterior border of epitrochanteric margin downwards and forwards towards ectotrochanteric tuberosity, slightly above which it subsides.
The upper moiety of surface thus mapped out is smooth compared with the lower, and presents the appearance of once having been covered by bursal tissue. The lower and posterior moiety is elevated and depressed, likewise roughened for the insertion of muscles.
Now in the posterior half of the lower surface are two well marked vertical depressions, one situated slightly in front and above the other one. And it is in this anterior one we have remaining a strong tuft of tendon, which, from the direction of its fibres, I believe to have been the Obturator internus. *
The posterior and lower one is that in which Professor Owen has located the insertion of the Quadratus femoris.
At the lower part of the anterior surface of the neck of the femur, just where it merges into the pretrochanteric surface, is a marked roughness with several of the fibres of above-named muscle still attached to it.
This is very interesting, as proving conclusively that this slight rough prominence is the representative of the smaller trochanter in mammalia, as had been foreseen by Owen.
Crurœus, part of Vasti.
Arising partly from the under surface of the base of ectotrochanteric tuberosity, partly from the ridge beneath it to the extent of half-an-inch, and partly from the linear ridge of the pretrochanteric face in the vicinity of
[Footnote] * I am aware that Professor Owen has stated Abductor magnus is inserted into this depression, but he has not had any specimen in which tendon has been left.
above tuberosity, are some muscular fibres that run down over anterior surface of femur, as if the muscle when entire had ensheathed the shaft of the bone. These fibres, I think, belong to the Vastus externus or anterior part of Crurœus.
The strong firm attachment of tendon of Biceps flexor crurris is well seen inserted into a strong roughness about 2 inches below head of the fibula on its outer surface.
Left Tibio-tarsal Bone.
On this bone there is a small slip of tendinous insertion left, which I believe to be part of the Sartorius.
It is into a depression on the inner side of the procnemial ridge about 4 inches below the head of the tibia at the apex of that well-defined triangular surface on the inner and anterior aspect of the bone, from which the second head of origin of the Gastrocnemius internus arises.