In the Arctic Seas Part 33

Scoriaceous hornblendic trap (boulders).

The sandstone of Byam Martin's Island is of two kinds--one red, finely stratified, pa.s.sing into purple slate, and very like the red sandstone of Cape Bunny, North Somerset, and some varieties of the red sandstone and slate found between Wolstenholme Sound and Whale Sound, West Greenland, lat. 77 N. The other sandstone of Byam Martin's Island is fine, pale-greenish, or rather greyish-yellow, and not distinguishable in hand specimens from the sandstone of Cape Hamilton, Baring Island. It contains numerous sh.e.l.ls and casts of a terebratuliform brachiopod, closely allied to the _Terebratula primipilaris_ of Von Buch, found abundantly at Gerolstein in the Eifel. On the whole, I incline to the opinion that the sandstones, limestone, and coal of Byam Martin's Island, are the corresponding rocks of Melville Island, Baring Island, and Bathurst Island, are low down in the Carboniferous System, and that there is in these northern coal-fields no subdivision into red sandstone, limestone, and coal-measures, such as prevails in the west of Europe. If the different points where coal was found be laid down on a map, we have in order, proceeding from the south-west--Cape Hamilton, Baring Island; Cape Dundas, Melville Island, south; Bridport Inlet and Skene Bay, Melville Island; Schomberg Point, Graham Moore Bay, Bathurst Island; a line joining all these points is the outcrop of the coal-beds of the south of Melville Island, and runs E.N.E. At all the localities above mentioned, and, indeed, in every place where coal was found, it was accompanied by the greyish-yellow and yellow sandstone already described, and by nodules of clay ironstone, pa.s.sing into brown hemat.i.te, sometimes nodular and sometimes pisolitic in structure.

No. XIV. GRAHAM MOORE'S BAY, Bathurst Island (Lat. 75 30' N.; Long.

102 W.).

Coal of the usual quality.

At Cape Lady Franklin, and at many other localities along the north sh.o.r.e of Bathurst Island, carboniferous fossils in limestone, clay ironstone b.a.l.l.s pa.s.sing into brown hemat.i.te, cherty limestone, and earthy fossiliferous limestone, with the same species of _Atrypa_ as at Byam Martin's Island, were found in abundance by Sherard Osborn, Esq., Commander of H.M.S. 'Pioneer,' in whose journal the following note respecting them may be found:--

"The above collection was delivered over to Captain Sir Edward Belcher, C.B., by Commander Richards, at 2 P.M., on 7th Nov. 1853."[35]

It is to be hoped that they may soon be made available for the elucidation of the geology of this most interesting portion of the Arctic discoveries.

No. XV. BATHURST ISLAND, Bedford Bay (Lat. 75 N.; Long. 95 50' W.).

In this locality abundance of vesicular scoriaceous trap rocks were found by Captain M'Clintock; they appear to me to be the representatives of the volcanic rocks found everywhere at the commencement of the carboniferous period.

No. XVI. CORNWALLIS ISLAND, M'Dougall Bay.

1. _Syringopora geniculata._ Journ. R. D. S., Vol. I. Pl. XI. Fig. 2.

2. _Cardiola Salteri._ Journ. R. D. S., Vol. I. Pl. VII. Fig. 5.

The Syringopore found at Cornwallis Island appears to be identical with the variety of the Irish carboniferous _S. geniculata_, in which the corallites are at a distance from each other somewhat exceeding their diameters, and in which the connecting tubes are about two diameters apart.

A question of very considerable geological interest is raised by the occurrence together of corals, in the same locality, of silurian and carboniferous forms.

I entertain no doubt of their being _in situ_, and occurring in the same beds, for the following reasons:--

1st. The Syringopores of Griffith's Island were found at an elevation of 400 feet above the sea, and, therefore, could not be brought by drifting ice.

2nd. The specimens were apparently of the same texture and composition as the native rock, whenever the latter was visible from under the snow.

3rd. I do not believe in the lapse of a long interval of time between the silurian and carboniferous deposits,--in fact, in a Devonian period.

4th. The same blending of corals has been found in Ireland, the Bas Boulonnais, and in Devonshire, where silurian and carboniferous forms are of common occurrence in the same localities.

5th. In the carboniferous beds proper of Melville Island and Bathurst Island, there were not found, so far as I am aware, any corals of the same character as those at Griffith's Island, Cornwallis Island, and Beechey Island, which could give a supply to be drifted to the latter localities in a Pleistocene sea. It is plain, from the height at which the corals were found that, if they were brought to their present localities by ice, it must have been during the period known as Post-tertiary, as the present conditions of drift-ice in Barrow's Straits do not permit us to suppose them to have been placed where we now find them by existing causes.

The occurrence of coal-beds in such high lat.i.tudes has been speculated on by many geologists--in my opinion, not very satisfactorily; as it is very difficult to conceive how, even if the question of temperature was settled, plants even of the fern and lycopodium type could exist during the darkness of the long winter's night at Melville Island. This difficulty is increased by the facts made known to us by the discovery of ammonites and lias fossils in Prince Patrick's Island by Captain M'Clintock.

IV.--_The Lias Rocks._

Many years ago it was a.s.serted by Lieutenant Anjou, of the Russian navy, that ammonites had been found by him in the cliffs on the south sh.o.r.e of the island of New Siberia, off the north coast of Asia, in lat. 74 N.

This statement, which was published in Admiral Von Wrangel's journal, attracted but little attention, until it was confirmed, as far as probability of such fossils occurring at so high a lat.i.tude is concerned, by the remarkable discovery of similar fossils by Captain M'Clintock, in lat. 76 20' N., at Point Wilkie, in Prince Patrick's Island.

In a paper, published by the Royal Dublin Society, in the first volume of their journal, p. 223, Captain M'Clintock thus describes the finding of these fossils:--

"After returning to Cape de Bray, we took up the provisions that the officer after whom it is called had left for us, and crossed the strait to Point Wilkie; reached it on the 14th May. This traverse was the more difficult from the great load upon our sledge, and the unfavorable state of the ice and snow. The freshly fallen snow was soft and deep, and beneath it the older snow lay in furrows across our route, hardened and polished by the winter gales and drifts, so that it resembled marble.

"On landing I found the beach low, composed of mud, with the foot-prints of animals frozen in it. A few hundred yards from the beach there are steep hills, about 150 feet in height, and upon the sides of these, in reddish-colored limestone, casts of fossil sh.e.l.ls abound. Inland of these, the ordinary pale carboniferous sandstone and cherty limestone re-appeared. The fossils are all small, and of only a few varieties, some being ammonites, but the greater part bivalves. They differed from any I had met with before, and the rock was almost brick-red; I picked up what appeared to be fossil bone (_Ichthyosaurus?_), only part of it appearing out of the fragment of the rock.

"Point Wilkie appears to be an isolated patch of lia.s.sic age, resting upon carboniferous sandstones and limestones, with bands of chert, of the same age as the limestones and sandstones of Melville Island. The eastern sh.o.r.es of Intrepid Inlet is composed of this formation; while the western, rising into hills and terraces, is of the underlying carboniferous epoch. At the western side of Intrepid Inlet I found upon the ice a considerable quant.i.ty of white asbestos, but did not ascertain from whence it had been brought."

The fossils thus found _in situ_, I have no doubt, belong to the lia.s.sic period; and as their geological interest is indubitable, I offer no apology for inserting here the following description, written by me on Captain M'Clintock's return to Dublin from his third Arctic expedition.

No. I. WILKIE POINT, Prince Patrick's Land (Lat. 76 20' N.; Long. 117 20' W.).

LIAS FOSSILS.

(a) _Ammonites M'Clintocki_ Journ. R. D. S., Vol. I. Pl. IX. Figs.

2, 3, 4.

_Monotis septentrionalis_, Journ. R. D. S., Vol. I. Pl. IX. Figs. 6, 7.

_Pleurotomaria_, sp. Journ. R. D. S., Vol. I. Pl. IX. Fig. 8.

Cast of some Univalve. Journ. R. D. S., Vol. I. Pl. IX. Fig. 7.

_Nucula_, sp.

(a) Ammonites M'Clintocki (Haughton).--_Testa compressa, carinata, anfractibus latis, lateribus, complanatis, transversim undato-costatis; costis simplicibus, juxta marginem interiorem levigatis; dorso carinato acuto; apertura sagittata, compressa, antice carinata; septis lateribus 4-lobatis._

This fine ammonite resembles several species common in the upper lias of the Plateau de Larzac, Sevennes, in France. It approaches _A. concavus_ of the lower Oolite, but is distinguished by having only four lobes on the lateral margins of the septa, and by its showing no tendency to a tricarinated keel. The following measurements give an exact idea of its form, as compared with that of the species mentioned:--

------------------+---------+-----------+---------+-----------+-------- |Diameter,| Width of |Thickness|Overlapping| Width |Inches. |last Spire.| of last | of last | of | | Diam.=100 | Spire | Spire |Umbilic.

------------------+---------+-----------+---------+-----------+-------- _A. M'Clintocki_, | 183 | 51/100 | 24/100 | 20/100 | 20/100 _A. concavus_, | 295 | 50/100 | 24/100 | 19/100 | 16/100 ------------------+---------+-----------+---------+-----------+--------

The princ.i.p.al difference here observable is in the somewhat greater size of _A. concavus_, and the larger umbilic of _A. M'Clintocki_. It certainly resembles this well-known ammonite very closely; and it appears to me difficult to imagine the possibility of such a fossil living in a frozen, or even a temperate sea.

The discovery of such fossils _in situ_, in 76 north lat.i.tude, is calculated to throw considerable doubt upon the theories of climate which would account for all past changes of temperature by changes in the relative position of land and water on the earth's surface. No attempt, that I am aware of, has ever been made to calculate the number of degrees of change possible in consequence of changes of position of land and water; and from some incomplete calculations I have myself made on the subject, I think it highly improbable that such causes could have ever produced a temperature in the sea at 76 north lat.i.tude which would allow of the existence of ammonites, especially ammonites so like those that lived at the same time in the tropical warm seas of the south of England and France, at the close of the Lia.s.sic, and commencement of the lower Oolitic period.

During the course of the same Arctic expedition in which these organic remains were found, Captain Sir Edward Belcher discovered in some loose rubble, of which a cairn was built on Exmouth Island (lat. 77 12' N., long. 96 W.), vertebral bones of, apparently, same lia.s.sic enaliosaurian. All doubt as to the reality of this discovery, and all idea of accounting for the occurrence of such remains by drift, must be abandoned, as the fossils found by M'Clintock were unquestionably _in situ_, and it is impossible to evade the consequences that follow to geological theory from their discovery.

Captain Sherard Osborn, also, found broken vertebrae of an ichthyosaurus, 150 feet up Rendezvous Hill, the north-west extreme of Bathurst Island: of these specimens, one lay among a ma.s.s of stone that had slipped from the N.W. face of the hill; the other was by the side of a ravine or deep watercourse on the southern face of the same elevation. I have no doubt but that they were _in situ_.

I am well aware that the question of light in the Arctic seas will be disposed of by some geologists, who will remind us that the saurians, and probably the ammonites, were endowed with a complicated optical apparatus, rendering them capable of using their eyes, not only for the distinct vision of objects differing greatly in distance, but also of using them, under widely differing conditions of light and darkness; and I readily admit the force of such observations.

But what are we to say as to the question of temperature? It was certainly necessary for an ammonite to have a sea free from ice, on which to float and bask in the pale rays of the Arctic sun; and therefore I claim a temperature for those seas, at least similar to that which now prevails in the British Islands: and I may add that the ammonite, from its habits, was essentially dependent on the temperature of the air, as well as on that of the water.

There is at present a difference of 495 F. between the mean annual temperature of Point Wilkie and Dublin; and if this change of temperature be supposed to be caused by a change of the relative positions of land and water, the temperature of Dublin, or of some place on the same parallel of lat.i.tude, must be supposed to be raised to 995 F.; while the temperature of the thermal equator will exceed 124--a temperature only a few degrees below that requisite to boil an egg! I reject, without scruple, a theory that requires such a result, which must be considered as a minimum; as it is probable that the ammonite required a finer climate than that of Britain for the full enjoyment of his existence.

The theory of central heat, also, appears to me to be open to the same objection, as a mode of explaining this remarkable geological fact; for it will simply add a constant to our present climates, leaving the differences to remain, as at present, to be accounted for by lat.i.tude and distribution of land and water. The astronomical theory of Herschel, also, which would account for former changes of climate by changes in the radiating power of the sun, would only increase the temperature at each lat.i.tude, leaving the differences as at present.

The only speculation with which I am acquainted, which is capable of solving this _opprobrium geologicorum_, is the hypothesis of a change in the axis of rotation of the earth, the admission of which, as a geological possibility, is mathematically demonstrable, and which has recently had some singular evidence in its favor advanced by geologists.

In 1851, I brought forward, at the Geological Society of Dublin, a case of angular fragments of granite occurring in the carboniferous limestone of the County Dublin; and explained the phenomena by the supposition of the transporting power of ice. In 1855, Professor Ramsay laid before the Geological Society of London a full and detailed theory of glaciers and ice as agents concerned in the formation of a remarkable breccia, of Permian age, occurring in the central counties of England; and still more recently the same agent has been employed by the geological surveyors of India to account for the transport of materials at geological periods long antecedent to those in which ice transport is commonly supposed to have commenced. The motion of the earth's axis would reconcile all the facts known, and it must be regarded as a geological desideratum to determine its amount and direction, and to a.s.sign the cause of such a movement. The solution of this problem I regard as quite possible.

It is well worthy of remark, that the arguments from the occurrence of coal-plants and ammonites strengthen each other; the coal-plants rendering the question of _light_, and the ammonites that of _heat_, insuperable objections to the admission of any received geological hypothesis to account for the finding of such remains, _in situ_, in lat.i.tudes so high as those of Melville Island, Prince Patrick's Island, and Exmouth Island.