204 Bibliography. 



on some uninhabited islands which exist on that coast, and the manure 

 that they leave is of inconceivable amount. At a distance the hills of 

 it resemble the mounds on some snowy plain. In the time of the Incas 

 there was so much vigilance in guarding these birds, that, during the 

 rearing season, no person was allowed to visit the islands under pain of 

 death, in order that they might not be frightened and driven from their 

 nests. Neither was it allowed to kill them at any time, either on or off 

 of the islands, under the same penalty.' Each district or territory also 

 had a portion of these islands allotted to it, the penalties for infringement 

 of which were very severe. From this extraordinary care it is proba- 

 ble that the Incas did not permit any remarkable consumption of this 

 valuable manure beyond the annual additions ; and the consumption 

 during the depopulation of South America by the Spaniards could, by 

 no means, have equalled those annual deposits. Even the greatest 

 thickness of seven to eight hundred feet might, without extravagant 

 calculation, be deposited in about three thousand years at the rate of 

 two or three inches a year. The feathers do not appear different from 

 those of birds of the present day. Mr. Blake, a member of our society, 

 who has visited these deposits, has a shell found in the Guano, very 

 much resembling the Crepidula fornicata of this coast, but not in any 

 way fossilized. On this coast it never rains, so that the deposits of ma- 

 nure are not, like those on other coasts, annually washed away." 



We have just received the new number of the society's Journal, con- 

 taining several interesting and valuable papers, particularly on the ich- 

 thyology of the North American lakes, by Dr. J. P. Kirtland, and on 

 the fishes of Brookhaven, L. I., by Mr. Ayres. 



16. Proceedings of the American Philosophical Society, held at 

 Philadelphia, for promoting Useful Knoioledge. Vol. Ill, (celebra- 

 tion of the hundredth anniversary.) — We have already given (Vol. xlv, 

 page 231) a list of the papers read before the American Philosophical 

 Society on the occasion of its hundredth anniversary in May last. This 

 stout pamphlet of 228 pages contains excellent abstracts of those pa- 

 pers, mostly from the accurate pen of the reporter, (Prof. Bache.) 

 Several of the most interesting papers read on this occasion have al- 

 ready appeared in extenso in our pages — e. g. by Messrs. Walker and 

 Kendall, on the Great Comet of 1843, (Vol. xlv, p. 188 ;) by Mr. 

 Redfield, on the Tides and Currents of the Ocean, (Vol. xlv, p. 293 ;) 

 by Prof. Norton, on the Tails of Comets, (p. 104 of the present num- 

 ber.) Many of the geological notices have also appeared under vari- 

 ous heads, and we shall probably have occasion ' to lay other valuable 

 matter from the same source before our readers. The meeting was 

 one of remarkable interest, and equally remarkable for the number of 

 valuable original memoirs and discussions which it developed. 



