ii PREFACE. 



I fear that most of the additions thus made of late years to the Crag Fauna, 

 coupled with the antagonism between the views of Dr. Jeffreys, concerning the 

 identification of many Crag shells with recent species (as expressed by the list 

 which accompanies the paper of Prof. Prestwich, in the twenty-seventh Volume of 

 the ' Journal of Geological Society ') and those of myself, will render the subject of 

 the Crag Mollusca, for some time to come, a subject of more perplexity than interest 

 to students of the upper tertiaries. 



I have now by inquiry in every quarter which afforded the slightest chance of 

 result exhausted all possible additions to the Molluscan Fauna of the Crag up to 

 the present time, doubtful or otherwise, and dealt with them in the present 

 Supplement. 



Dr. Lycett has (after a lapse of more than twenty years) written to me that the 

 attribution of an analysis of the Myadce to Prof. Morris made in the footnote to 

 p. 265 of my second volume of the " Crag Mollusca " was an error, and that the 

 analysis was entirely his own. I take this opportunity, therefore, of acknowledging 

 the error, and of expressing my regret for it. 



s. Y. WOOD. 



iXOYEMBEB, 1878. 



