91 



European Strata. 



Upper Miocene 



The principal deposit of this period in which insect remains 

 have been detecetd is the great lacustrine formation of (Eningen 

 in the Valley of the Rhine, between Constance and Schaffhausen. 



The (Eningen Strata consist, according to Lyell, of a series 

 of Marls and Limestones, many of them thinly laminated, and 

 which appear to have slowly accumulated in a lake, probably fed 

 by springs, holding carbonate of lime in solution. The organic 

 remains have been chiefly derived from two quarries, the lower of 

 which is about 550 feet above lake Constance, and the upper 

 quarry is about 150 feet higher. 



The insect fauna of (Eningen appears to have been richer 

 than that now inhabiting any part of Europe. From the beds of 

 this formation 844 species have been discovered by Professor 

 Heer, and his diligent researches had, in 1867, brought to light 

 5,081 specimens, viz. : — 



5081 



This number of specimens comprised 844 species, viz. 



844 



In my introductory observations I alluded to the conclusions 

 which might be arrived at as to the climate and vegetation of a 

 former epoch from the study of its fossil insects. I will now 



