Notice of Birds observed in the Island of Heligoland. 85 



Larus Rossii 

 Sterna cantiaca 

 ,, anglorum 



caspia 

 , , Dougallii 



hirundo 

 , , macroura 

 ,, leucoparia 



nigra 

 , , minuta 

 Lestris cataractes 

 „ pomarina 



Lestris parasitica 

 ,, crepidata 

 Procellaria glacialis 

 „ Leachii 

 „ pelagica 

 ,, cinerea 

 ,, anglorum 

 Podiceps cristatus 

 „ ruficollis 

 ,, cornutus 

 , , auritus 



Podiceps minor 

 Colynibus glacialis 

 arcticus 

 ,, septentrionalis 

 Uria troile 



„ tringria(?) 



„ arra 



jj grjlle 

 Alca arctica 



„ torda 



„ alle 



IV. On the Danger of Hasty Generalization in Geology. 

 By Alexander Bryson, Esq. 



After deducing examples of hasty generalization, and show- 

 ing the frequency of erroneous conclusions drawn from scanty 

 data, he gave the following example, of which he was him- 

 self guilty : — " In the summer of 1856, a few friends joined 

 me in a yachting expedition, to geologise among the islands of 

 the Firth. Among other islands we visited Inch Mickery, 

 and spent some hours in examining its structure. On the 

 southern summit of the rock, a quantity of lead was found, 

 filling up many of the interstices of the trap, which had, be- 

 sides, a very scorched appearance. This circumstance natu- 

 rally excited our curiosity, and many theories were formed 

 to unriddle the enigma, but in vain. We carefully examined 

 the island, but could not find a trace of a fire by which the 

 lead could have been melted, except at such a distance from 

 the rock as to render the idea of lead being carried so far 

 without cooling inadmissible. Then the lead had run into the 

 crevices of the rock, showing that it must have been very 

 fluid when it fell. The absence of every trace of carbon 

 around the lead, or at all near the rock itself, was very puz- 

 zling. About this time our talented member, Dr Heddle, had 

 announced the occurrence of native lead embedded in meteo- 

 ric iron, and I at once held my Inch Mickery lead as truly 

 meteoric in its origin. This idea was rendered the more 

 probable, as Dr George Wilson, who kindly analysed it, failed 

 to detect in it any trace of silver. Professor Fleming, al- 

 though he scouted the notion of its meteoric origin, kindly 

 accompanied us on a second visit to the island. After a per- 

 sonal examination, he was unable to throw any light on the 



