IOWA ACADEMY OP SCIENCES. 99 



The forest bed at Washington has often been referred to. 

 Buried forests have been reported in the region at Murray, 

 Fontanelle, and points in Taylor county and, while the phe- 

 nomena have not yet been carefully collected and studied, 

 enough is known to prove that the facts are not isolated; and 

 some of them, at least, seem worthy to serve as a basis for 

 generalizations. 



The exposure near Hastie, first described in a meeting of this 

 Academy* and more fully described in the reports of the Geo- 

 logical Survey t, is probably to be considered in this connection. 

 In view of the results of the past season's work in the discovery 

 of correlative evidence it now seems that the argument from 

 erosion then suggested is a good one and that there is an 

 important time break between the gravels and the Kansan 

 drift. Certainly a time break which was sufficient to allow the 

 Des Moines to clear out of its old valley forty feet of drift so 

 completely that only a few scattered remnants are left, is not to 

 be considered trivial. 



SUMMARY. 



In considering the conclusion to be drawn from the evidence 

 now in hand the remarks relative to the value of the various 

 lines of evidence should be kept in mind. 



First. — It is submitted that there is widespread evidence of 

 buried forest and peat beds in the region. It is admitted that 

 nothing of importance bearing on the character of this flora as 

 regards climate is known. It is further admitted that these 

 notes on forest beds have not been sifted, and much of the evi- 

 dence is of uncertain value. It is, on the other hand, to be 

 noted that certain of the beds are well attested as to position, 

 occupying a horizon fitting well with the hypothesis of Iwo 

 drifts, and that some are of a thickness worthy of considera- 

 tion. Upon the whole, however, the argument from forest 

 beds alone probably has but slight value. 



Second. — Buried soils have been shown to be not unknown, 

 though the value of the evidence derived from them is uncer- 

 tain. 



Third. — It has been impossible so far to apply the ordinary 

 tests based on leached and ferretto zones to the sub-Aftonian. 



Fourth. — Waterlaid beds are present at several points at the 

 Aftonian horizon. In Polk county they are believed to be 



* Keyes and OaU", Proc. Iowa Acad. Sur., 1890-91, p. 30. 

 + Vol. VII, Geology of Polk County, pp. 336-338, 1897. 



