POST-TEETIARY 



ENTOMOSTKACA OF SCOTLAND 



(INCLUDING SPECIES EROM ENGLAND AND IRELAND). 



INTRODUCTION. 



The larger part of the Ostracoda, described in the following Monograph, occur in the 

 Glacial and Post-glacial beds of Scotland, and their geological position is a matter of 

 very considerable importance. A mere catalogue of species under the vague general 

 title of " Post-tertiary " would have little or no geological value. The numerous 

 deposits, which such a term as " Post-tertiary " includes, are widely separated from each 

 other, both in age and in the climatic conditions they represent. A vast series of clays, 

 sands, and gravels were deposited during the epoch intervening between the commence- 

 ment and cessation of more vigorous conditions of climate than are now prevalent in 

 Great Britain ; while that cessation itself was certainly gradual and may possibly prove 

 to have been accompanied by its own recurring periods of increased heat and returning 

 cold. It would be foreign to the purpose of this Monograph to discuss any theoretical 

 explanations of the phenomena of the Glacial Epoch ; but we shall endeavour to indicate 

 the precise characters of the various beds containing the species of Ostracoda we 

 describe. Whatever position in the great sequence of deposits any bed we have 

 examined may ultimately be pronounced to occupy, we trust that its identification with 

 our description may be sufficiently easy to permit the facts we have ascertained 

 concerning its composition and fauna to be of service to future students. 



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