118 ON THE OBJECTS OF A COLLECTION OF INSECTS. 



appreciated by those who have passed from ignorance to 

 knowledge, and have felt how immeasurably their enjoyment 

 of life has been heightened, as they have become better able 

 to appreciate the wonderful works of God. 



The connexion between different sciences is always very 

 interesting, and that between Zoology, Physical Geography 

 and Geology is no exception to the rule. Lists of species 

 have long been used as excellent tests of the age of deposits 

 found in different parts of the world, and the labours 

 of Professor Edward Forbes have made known to us that 

 interesting evidence on the geography of ancient times may 

 be obtained in the same way from a careful examination of 

 lists of species. In his paper on the " Geological Relations 

 of the existing Fauna and Flora of the British Isles," he 

 shows that out of sixty-five species of testaceous molluscs 

 which are common to the coasts of the United States and of 

 Europe, fifty-one are known as glacial fossils. Of the re- 

 maining fourteen, two are pelagic wandering mollusca ; one 

 Teredo Navalis is carried about in floating wood, two are 

 small species living in stony ground, near high-water mark, 

 and therefore not likely to be found fossil : three are 

 Chitons, which fall to pieces soon after death, two are doubt- 

 ful, and the other four may very probably yet be found 

 fossil. The inference which Professor Forbes draws from 

 these facts is, that "not a single littoral or coast-inhabiting 

 mollusc has found its way across the Atlantic, in either 

 direction, since that ancient time, anterior to all human 

 records, and probably long anterior to the appearance of 

 man on our earth, when an Arctic Sea, inhabited by a 

 limited and uniform fauna, extended from the then western 

 coasts of Siberia into the heart of North America, and 

 southwards in Europe to the parallel of the Severn, and in 



America to near that of the Ohio There could not 



then have been such a separating abyss between Northern 



