188 WicJcham — Fossil Beetles from the Sangamon Peat. 



colder, a considerable number of tlie recent allies of the fossils 

 being known from a more northern habitat. On the whole, 

 the fauna had a boreal aspect though by no means so decidedly 

 boreal as one would anticipate under the circumstances. 



Examination of the Illinois collection indicates the presence 

 therein of ten determinable species belonging to seven genera 

 and four families, the Carabidse, Dytiscidse, Staphylinidse and 

 Chrysomelidse. These families contain, as well, the bulk of 

 Scudder's Scarborough species, in the proportion of 36, 8, 19 

 and 2 respectively — that is, 65 out of the 76 which he has 

 described. Five of the genera are common to both collections 

 but all of the species appear to be quite certainly different. 

 The basis for deductions as to climate is not very broad but, 

 judging from the presence of Carabus moeander sangamon 

 and Chleeniics plicatipennis, the general northern flavor of the 

 remaining species and the entire absence of any without fairly 

 close recent boreal allies, I think we are quite justified in 

 assuming that conditions were, at any rate, more rigorous than 

 in southern Illinois at present. Probably they were at least as 

 severe as in Ontario at the date of formation of the Scarbor- 

 ough beds. It is true that all of the genera are now living in 

 Illinois but they also occur very far to the north, extending in 

 part to the shores of the Arctic Ocean and we must take into 

 account the entire absence of anything characteristically 

 southern. A glance at the notes following the descriptions 

 will show that the near relatives of all the fossils in this col- 

 lection are of northern range. 



One might hope that the beetles would throw some light 

 upon the identification of beds containing their remains and 

 allow us to decide with some certainty whether or no the 

 Scarborough deposit and the one now under investigation 

 really belong to the same interval. The matter is complicated, 

 however, by our ignorance of Pleistocene insects. Aside from, 

 the two collections noted above, we are acquainted, in this 

 country, only with the probably more ancient Port Kennedy 

 fauna, that of the widely distant Pancho la Brea asphalt 

 deposit and an occasional scattering species from some other 

 point. It has already been brought out that the species of the 

 Scudder report are all different from those of the present 

 paper, though in general closely allied. The differences are 

 not great enough to indicate any wide dissimilarity in ecolog- 

 ical conditions nor separation by a long period of time. On 

 the other hand, the likenesses do not prove the deposits to be 

 synchronous. It is apparently recognized that the Sangamon 

 interval was of long duration (20,000 to 100,000 years*) and 

 even if both Scarborough and Mahomet beds were laid down 



* Osborn, The Age of Mammals, p. 447, 1910. 



