VOL. LIV.] PHILOSOPHICAL TRANSACTIONS. §1 



All this on the supposition that the masses of the earth and moon are as 

 39.788 and 1. Hereafter, when the moon's distance shall be more certainly 

 known, that element may be corrected, and the operations repeated. As to the 

 sun's parallax 8^", it cannot be much affected by any future determination of the 

 moon's distance. Nor is it here assumed of that quantity, at random; but from 

 a theorem deduced from the established principles. I am, however, too diffident 

 of myself to communicate it at present: because, though it agrees very well 

 with Mr. Short's conclusion from the transit of Venus, it differs considerably 

 from that which a very learned and justly celebrated author has lately published. 

 — Note, The periods, as assumed in this paper, are: a sidereal year of 

 365.2563923 days: the periodical month 27 .321 65835 days. 



V. An Attempt to Account for the Origin and the Formation of the Extraneous 

 Fossil commonly called the Belemnite. By Mr. Joshua Piatt, p. 38. 



The public has of late been agreeably entertained with descriptions of many 

 curious fossils discovered in different parts of this kingdom ; but very little has 

 been offered with a view to ascertain their origin and formation; a point of much 

 greater importance to a curious mind, than the most accurate descriptions, or 

 the neatest delineations. It may indeed be thought unnecessary at this time, to 

 say any thing of the origin of extraneous fossils in general ; all our modern na- 

 turalists being fully convinced, that they are the exuviae or remains of animals 

 and vegetables, and the greater part of them of marine production. But as to 

 their particular origin and formation, in what manner they were produced in the 

 recent, and how and with what matter they afterwards became impregnated in 

 their fossil state, all this is a field of natural inquiry, that has been very much 

 neglected, though it is the most fertile and productive of useful and entertaining 

 knowledge. Besides, considering it in this view, the recent and fossil remains 

 would be found to throw a mutual light on each other, and the naturalist would 

 not be so often at a loss to class every new fossil acquisition, of which the recent 

 specimen is not to be found, esj^ecially whenever the fossil has any thing seem- 

 ingly equivocal in its formation, so as on a superficial inspection to render the 

 matter doubtful whether the body belongs to the animal or vegetable kingdoms, 

 or indeed to either of them. 



One of the first note is the belemnite, which has not until very lately been 

 even ranked among the marine productions ; but whose origin and formation 

 have never yet been fully explained. Not to enter into a minute detail of the 

 several species of the belemnite, the history of this extraneous fossil, or an 

 attempt to account for the origin and formation of it, so far as they can be dis- 

 covered and confirmed by reasonings drawn from facts and experience, is the 

 object of the present inquiry. Mr. P. confines himself to two species of the 



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