Page images
PDF
[ocr errors][ocr errors][graphic][ocr errors][graphic][graphic][ocr errors][ocr errors][ocr errors][graphic][ocr errors]

except in such specimens as fig. 1 : these are probably only the remains of fragments, as they never consist of any fixed number of rings. We may refer these fossils perhaps to the Linnaean genus Dentalium, and

the species may in that case be named D. annulata. March, 1834.

[graphic]

The valley of the Ponar river, where the peculiar appearances represented in my notice of March are found, is so hot and unhealthy, that it is quite deserted at this season, and the path leading to it is so diflicult that for eight or ten miles it must be travelled on foot ; a performance which an European could not accomplish with safety except in the cold weather.

This will account for my not being able to send you at present the specimens you require ; and whether I be permitted to remain in this neighbourhood long enough to be enabled to procure the specimens is somewhat uncertain.

These considerations induced me to make un efl'ort to procure some of the fossils without delay; and on receipt of yours of the 27th ultimo, I despatched a few natives to the spot, provided with such implements as I could procure for breaking rocks, and placed them under the direction of a person who was with me at the time I first observed the fossils.

The men have now returned unsuccessful in their attempts to break the rocks, containing the specimens for which they were sent.

Under these circumstances, it may be the most prudent way, before introducing a new, real, or supposed species, to inquire if the figures in question be really organic remains, or mere delineations formed by a peculiar arrangement of the distinct concretions of the rocks in which they are found. The consideration of this point is suggested partly by the remarks contained in your letter, and partly by a fragment of transition limestone,which has been brought to me containing ring-shaped delineations on its surface, which, if not quite similar to those represented in my former notice, are at least nearly allied to them. The

accompanying drawing (fig. 4) is a faithful representation of the ap

pearance on the limestone ; the stone from which it was taken is much at your service : it was brought from the spot in which the other specimens are found. They occur in great quantity, and pass progressively into those represented in my first notice, and both appear to be but the two extremes of the same thing*. They occur only in rocks of the same age, whether these be slate or limestone. On the other hand, we know that mere delineations on the surface of particular rocks, differ with the constitution of the rock in which they occur, are uncertain as to size, and are without any fixed regularity in the proportion of the different parts to each other; proving them to be either the result of mechanical increment or of chemical attraction. Respecting organic fossils, Caousrnnr says, " They are distinguished by an organic structure more or less imperfect, of which as long as they bear any marks we are to reckon them as fossils of a foreign* species.” With respect to your remarks on the rings, I can only account for the part of the lower and upper portions being both visible, by supposing the bodies to which they belonged to have been soft enough to yield to lateral pressure, and to have been thus converted into superficial substances. Others again, as fig 1, may have been exposed to compression, which acted longitudinally, so as to destroy their length, but preserve the lateral dimensions.

‘' Since the above was written I have met with an extremely interesting

paper on Belemnites in the Phil. Transactions, 1754, by Mr. Bmmnnn, to which a plate in attached, containing various figures. No. 16 bears a strong resemblance to fig. 3, except that the Ponar fossil appears to have been perforated in the centre, while Mr. B.’s figure is merely grooved by external strim, but in this respect, Mr. B. remarks, there is great variety—may not the Ponar fossil be a Belemnite, so worn and changed by the lapse of ages, as only to present the marks of former cells: the outer crusts being destroyed, and the traces of septa and siphuncle only remaining—but taking the aggregated form of the rings,and assuming them to have been a shell; it certainlywouldhave agreed with the moderngenus Dentalinm; but if by that we imply also the nature of the animal which formerly occupied it, we then go too far in attempting to define so imperfect a trace of the organization of a former world. In a chronological arrangement this fossil must take its place amongst the remains of the earliest created beings.

It is unnecessary to remark that this explanation would not apply to any univalve shell with a regular spire; and that of univalve shells without regular spires, Dentalium is the only genus to which these appearances can be referred. The generic character of Dentalium is “ shell awl-shaped, open at both ends.” The rings are sufliciently characteristic to distinguish the species ; but until we can procure good specimens, it is premature to be positive as to the place these fossils should occupy. I know the danger of touching fossil drawings without the specimens before one’s eyes, and what shakes my confidence in the drawing attached to theformer notice now is, that though it was accurately sketched from the specimens, yet it was finished from

recollection only. With respect to the drawing here attached, it is calculated to mis~

lead as to the true nature of the fossils ; were the figures complete, they would be found to be awl-shaped, the ends nearly equal in size,

‘ “ Foreign species,” as here used, means foreign substance.

and apparently open ; there is also an appearance something like a detached spire, but this I take to be nothing but the fore-shortening of the rings, such as is represented in fig. 1, but less perfect. I may add, that I have not seen the trace of a spire or a whorl in all these appearances. Orthocera are long, straight, tapering shells, characters not one of which answer to these remains. One of the figures in the accompanying drawing resembles a fragment of an orthoceratite, but were it more complete, it would be awl-shaped. Now as to the mineral composition of the fossil in transition slate, I found the rings to be composed of a fine siliceous sandstone. In the limestone they are in_ corporated with, and similarly constituted, as the rock itself, so that they would elude the character of fossils, were it not for their more perfect existence in the transition slate. Having pointed out these appearances to your notice, as well as the locality in which they occur, their nature may be further inquired into by others, should the term of my residence in this quarter deprive me of the opportunity.

May, 1384.

[Being rather sceptical as to the appearance of the under-surface of the rings represented in Dr. McCLELLANn’s first notice, we mentioned our doubts to him, and were favored with the further explanation, dated in May, which by some accident was mislaid; and we were forced to repeat our request for a duplicate. The great distance will account for the delay which has unfortunately occurred in its appearance. We are not yet satisfied, however, that the impressions are truly of a fossil nature, and we doubt whether any geologist would venture from such indistinct traces to pronounce an opinion of the genus of the fossil.—En.]

[graphic]

VI.——Further notice of Influence of the Moon on AtmosphericaZPlreu nomena. By the Rev. R. EVEREST, M. G. S. &c.

In my last paper, I urged the probability of the dew-points varying with the declination of the moon, and from that was naturally led to the conclusion that the rain-falls would vary in a similar manner. Having, therefore, obtained the Nautical Almanack for the year 1823, and having by me the register of rain-fall for the two months of August and September in that year, I made out a table for comparison, placing the rain-fall in one column, and the declination of the moon in an adjoining one beside it, and her semi-diameter in the next to that; on the other side, the days of the month in succession, and on the other side of them again, the declination of the sun. If we recollect that the latitude of Calcutta is about 22° 23’ N.I we may see by this table that a greater proportion of rain falls when the declination of the moon (either north or south) is near about the same as the latitude of the place, and that the proportion lessens as

« PreviousContinue »