Animals of Peru. 1727 



sively more and more solid from the surface downward, a circumstance naturally ac- 

 counted for by the gradual deposit of the strata, and the evaporation of the fluid par- 

 ticles. Guano is found on all the islands, and on most of the uninhabited promonto- 

 ries of the west coast of South America, especially in those parts within the tropics. I 

 have often been assured that beds of guano several feet high, covered with earth, are 

 found inland at some distance from the sea ; but I never met with any, and I have 

 some doubt of the correctness of the statement. If, however, these inland strata really 

 exist, I am inclined to believe that they can only be found on hilly ground ; and in 

 that case they afford strong evidence of a considerable elevation of the coast. 



" Guano is formed of the excrements of different kinds of marine birds, as mews, 

 divers, sheerbeaks, &c. ; but the species which I can name with more precision are the 

 following, — Larus modestus, (Tsch.), Rhincops nigra, (Linn.), Plotus anhinga, (Linn.), 

 Pelecanus thayus, (Mol.), Phalacrocorax Gaimardii and albigula, (Tsch.), (Pelecanus 

 Gaimardii, Less., Carlo albigula, Brandt), and chiefly the Sula variegata, (Tsch.) 



" The immense flocks of these birds as they fly along the coast appear like clouds. 

 When their vast numbers, their extraordinary voracity, and the facility with which 

 they procure their food, are considered, one cannot be surprised at the magnitude of 

 the beds of guano, which have resulted from uninterrupted accumulations during many 

 thousands of years. I kept for some days a living Sula variegata, which I fed abun- 

 dantly with fish. The average weight of the excrement daily was from three and a 

 half to five ounces. I have no doubt that when the bird is in a state of freedom the 

 weight must be much greater, for these birds are constantly plunging into the sea, in 

 order to devour the fishes which they find in extraordinary masses around all the 

 islands. When an island is inhabited by millions of sea-birds, though two-thirds of 

 the guano should be lost while flying, still a very considerable stratum would be accu- 

 mulated in the course of a year. 



" The marine birds nestle on the uninhabited islands, or on rocks near the shore ; 

 but they never settle on the flat beach, or any place distant from it inland. On this 

 fact I ground my conjecture that those beds of guano in the interior, which may have 

 been removed from the shore by important elevations of the coast, are to be found only 

 on hills. 



" During the first year of the deposit the strata are white, and the guano is then 

 called guano bianco. In the opinion of the Peruvian cultivators, this is the most 

 efficacious kind. It is found in the Punta de Hormillos, on the islands of Islay, 

 Jesus, Margarita, &c. 



" As soon as the dealers in guano begin to work one of the beds, the island on 

 which it is formed is abandoned by the birds. It has also been remarked, that since 

 the increase of trade and navigation, they have withdrawn from the islands in the 

 neighbourhood of the ports. 



" Much has recently been written on the employment and utility of guano ; but 

 the manner in which it is applied as manure in Peru seems to be but little known. 



graphy guano, which is also followed in Spanish America, is quite erroneous, for the 

 Quichua language is deficient in the letter G, as it is in several other consonants. The 

 H, in the commencement of the word, is strongly aspirated, whence the error in the 

 orthography of the Spaniards, who have sadly corrupted the language of the Autoch- 

 thones of Peru. 



