236 Prof. BucKLAND on Coprolites. 



Appendix. 



The facts established in this paper seem connected with the formation of the remarkable sub- 

 stance called guano on the coast of Pern, and on many islands adjacent to it. This guano is 

 composed of an accumulation of the dung and urine of sea-birds, and occurs in beds fifty or sixty 

 feet thick. These beds are often covered over with drifted sand, and, during many centuries 

 past, have been extracted for manure. 



In Ferussac's Bulletin for January 1829, Art. Chemistry, p. 84, there is an abstract of a 

 Memoir on the Guano of Paxaro, by Mariano di Rivero, director of the Corps des Mines in 

 Peru and Lima, 1827. He states that it is certainly nothing else than an accumulation of the 

 excrement of sea-birds that have come to pass the night on these spots during a long series of 

 years : he further adds, that certain deposits of it were worked from time immemorial before the 

 conquest. In the time of the Incas, the use of it was under legal regulations, to prevent waste, 

 and during the breeding season of the birds, no one, under penalty of death, was allowed to land 

 on the islands on which it was forming. 



Since the time of the Spaniards the preservation of it has been neglected ; and its reproduction 

 diminishes as vessels passing more frequently along the coast, frighten away the birds. In modern 

 times, the average consumption of guano for manure has been about 6250 tons per annum, for 

 which the duty paid at the ports has been about 40,000/. sterling per annum. 



Vauquelin and Fourcroy analysed some specimens of it brought home by Humboldt, and found 

 uric acid partly saturated by ammonia and lime, and oxalic acid partly saturated by ammonia 

 and potash ; also phosphoric acid combined with the three same bases, with very small quantities 

 of muriate of ammonia, a little fatty matter, and a little quartzose and ferruginous sand. 



We may add this guano to our series of Coprolites, by the name of Ornithocoprus. See also 

 Ure's Chemical Dictionary, Art. Guano. 



Postscript. 



During a recent visit to Lyme Regis, I have ascertained that the lias at that place contains 

 other cylindrical concretions resembling Coprolites, which yet seem not to be of fiecal origin, but 

 simply mineral concretions formed like small septaria in clay, or flints and nodules of pyrites in 

 chalk; tliey agree chemically with Coprolites in containing much phosphate of lime, but differ 

 from them in their relations to their matrix, in structure, and in the organic remains which they 

 envelop. 



I find also that phosphate of lime occurs in other secondary strata, more generally than has 

 hitherto been supposed. Dr. Daubeny has undertaken the analysis of several specimens which I 

 suspect to contain it, and 1 hope shortly to lay the result before the Geological Society : at pre- 

 sent, I deem it right to mention these circumstances by way of caution, as they tend to increase 

 the difficulty of identifying Coprolites wherever they may occur, and render it impossible for 

 chemistry alone to decide affirmatively respecting any specimen that is the subject of our exami. 

 nation. Still the evidence of chemistry is essential ; and when it has shown that a specimen con- 

 Uins phosphate of lime, we must further ascertain its relations to the matrix, its external and 

 internal structure, and the character of the organic remains enveloped in it, before we can pro- 

 nounce whether it be a genuine Coprolite, or a pseudo-coprolitic concretion of phosphate of lime. 



