I 



Wickham— Fossil Beetles from the Sangamon Peat. 137 



Art. XIII. — Some Fossil Beetles from the Sangamon Peat ; 

 by H. F. Wickham. 



Although the insect life of the ISTorth American Tertiaries 

 has received considerable attention, that of our Pleistocene is 

 relatively little known. Our ignorance of the exact distribu- 

 tion of insects in this latter period is due in part to the ajDpar- 

 ent scarcity of deposits containing reasonably well-preserved 

 remains and, in almost equal degree, to the disinclination 

 among entomologists to give the more or less fragmentary^ 

 material the close study necessary for determination. 



Most of the known I^orth American Pleistocene fossil 

 insects are from the clays, peats and asphalts. Nearly all of 

 them, so far as recognized, are beetles, the hard exoskeleton of 

 this group resisting destructive agencies much better than the 

 comparatively delicate integuments of other orders. It is also 

 evident, from the nature of the remains, that ground beetles 

 and water beetles are much more likely to be preserved than 

 those living upon plants, the result being that collections made 

 in different sections of the country may have a similar physi- 

 ognomy. While this renders the identification of new finds 

 more difficult, it really gives a much better basis for compara- 

 tive work than if the same number of species were scattered 

 through many families. We are able, for example^ to com- 

 pare the Carabidse, Dytiscidse and Staphylinidse of one loca- 

 tion with species of the same families from other places. 



During the past two years, I have received from Professor 

 T. E. Savage sendings of Coleopterous remains which he col- 

 lected in an exposed peat seam on the north bank of the San- 

 gamon Piver near Mahomet, Champaign County, Illinois. 

 This peat lies above the Illinoisan and below the Wisconsin 

 drift. There is a slight development of loess or loess-like silt 

 above the peat and below the Wisconsin, and Professor Savage 

 considers that the reference of the bed to the Sangamon stage 

 is rather definitely proven. 



This collection allows us to make a comparison of two fairly 

 widely separated Korth American faunge which have been 

 assigned to the same interglacial stage, since Doctor S. H. 

 Scudder has reported quite fully upon a series of Coleoptera 

 from the Scarborough beds near Toronto, Canada,* considered 

 as belonging to the Sangamon interval. He recognized 76 

 species of 38 genera and 8 families. From these he reached 

 the conclusion that the climate of Ontario, at the time of their 

 deposition, was very similar to that of to-day or perhaps slightly 



* Contributions to Canadian Palaeontology, vol. ii, part II, Ottawa, 1900. 



