XVIU INTRODUCTION. 



ing " the sunny south." Instead of searchmg the ex- 

 posed beaches and rocky headlands only, if collectors 

 had betaken themselves also to the fishing stations, and 

 searched the boats and lines, they might have found a 

 great variety of interesting species. The pastures, woods, 

 marshes, lakes, ditches, streams, and estuaries, also, are 

 far from being so unprolific as they might seem. The 

 nature of the rock, it appears to me, makes little differ- 

 ence. The granite of the Bullers of Buchan, and the 

 gneiss of the Cove, are not less productive than the con- 

 glomerate of Stonehaven, or the greywacke and sand- 

 stone of the Northern coasts. The only difference 

 seems to be, that individuals are more numerous in the 

 secondary than in the primary tracts ; for the same 

 species occur in both ; and I am not aware of any geolo- 

 gical deposit in the district, or any particular kind of 

 rock, fostering any peculiar species, "with the exception 

 of Helix hispida, and Bulimus obscurus, which have 

 been found among sandstone near Stonehaven, but as 

 yet nowhere else. 



A search continued at intervals, for twenty-two 

 months only, has produced three hundred and forty 

 species — a number greater than might reasonably be 

 expected ; and there can be little doubt that many species 

 remain to be added, insomuch that, I think, the entire 

 number will ultimately exceed four hundi-ed. When 

 the bays are dredged, and the rocky coasts more mi- 



