60 



Analysis of the Coprolites of Birds. 



The samples examined by Dr. Ure were the purest gnano fur- 

 nished by the governments of Peru and Bohvia. Casting the 

 eye over all these results, we draw two inferences : 1st. If your 

 coprolite had been the excrement of a reptile, it must have been 

 placed in peculiar circumstances to have had its uric acid so 

 fully removed. If removed, it has left a compound more nearly 

 resembling that of guano. This is decisive. 2d. It is seen from 

 Prof Johnston's results, that it is possible to have all the uric 

 acid removed in one case, and 0-8 only remaining in another, 

 leaving phosphate not differing much in its proportions from that 

 found in your coprolite. 



If we recur with these facts in mind to your coprolite, and 

 bear in mind its urates, phosphates of lime and magnesia, car- 

 bonate of lime, sulphates, muriates, and organic matter, volatili- 

 zed at a red heat, and silicates, the conclusion seems inevitable, 

 that it has been dropped by a bird belonging to the class which 

 has deposited the beds of guano.f 



* Inchiding urate of ammonia, and 11 water. 



t Within a few weeks ray attention was called by reading an article in the 

 London Mech. Mag. to a paper by MM. Girardin and Preisser on fossil bones, 

 which I have since read in Ann. de Chimie for November, 1843. At page 370 is 

 the following account of the results of an examination of the coprolite of an Ich- 

 thyosaurus from Lyme Regis, Eng. The ingredients are slated in the order of 

 their greatest amount. Subphosphate of lime, (much); carbonate of lime ; urate 

 of ammonia; urate of lime; silica; oxalate of lime, (small); alkaline sulphates; 

 fish scales. S. L. D. 



Octoher 2M, 1844. 



