Notice of Birds observed in the Island of Heligoland, 85 
Larus Rossii 
Sterna cantiaca 
Lestris parasitica Podiceps minor 
,, crepidata Colymbus glacialis 
Procellaria glacialis arcticus 
anglorum 
caspia 
Leachii septentrionalis 
pelagica Uria troile 
cinerea tringria (?) 
anglorum „ arra 
, , Dougallii 
,, hirundo 
macroura 
leucoparia 
Podiceps cristatus ,, grylle 
„ ruficollis Alca arctica 
cornutus „ torda 
auritus „ alle 
, , minuta 
Lestris cataractes 
„ pomarina 
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, Avho 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 
