98 IOWA ACADEMY OF SCIENCES. 



will soon be extensively reworked and final evidence upon some 

 of these questions will then be at hand, no attempt will be 

 made for the present to determine the balance of probabilities 

 between the two hypotheses. 



CO-ORDINATE PHENOMENA. 



Before taking up the question of the presence of two drifts 

 in the larger region it will be advisable to mention certain 

 additional exposures. In the immediate vicinity of Afton a 

 buried peat bed has been reported from several wells, and speci- 

 mens of peat collected by Mr. William Haven, leave no doubt 

 as to its nature. This bed is found at a depth of about forty 

 feet in situations which seem to indicate that it is lower than 

 the base of the loess. 



Following down Grand river traces of the gravels are occa- 

 sionally seen and at Reynolds ford, near where Union and 

 Decatur counties corner, the beds are exposed with a thickness 

 of 15 feet. They rest as at the exposure already described 

 upon a blue-black bowlder clay of peculiar physical character 

 and unlike the usual blue clay of the Kansan. In the southern 

 portion of Decatur county below Davis City (southwest of 

 northwest section 18, Hamilton township) is another exposure 

 of bowlder clay of this character and over it are some beds of 

 stratified material. Between the two points south of a small 

 country town called Terre Haute (section 28, Burrell township) 

 is an exposure in the south bank of the river showing a soil 

 below yellow bowlder clay answering to the Kansan and having 

 here stratified material below. This exposure is not altogether 

 satisfactory and has been discussed elsewhere* but should be 

 kept in mind in offering an interpretation for the region. 



In the southwestern portion of the county a forest bed has 

 been reported from several wells. Mr. Fitzpatrick has noted 

 it at Lamoni at a depth of 85 feet with 100 feet of bowlder clay 

 below. In ' Harrison the adjoining county in Missouri, Dr. 

 Keyes informs the writer that a peat bed as much as nine feet 

 thick has been found at considerable depths. Near Osceola 

 and again near Leon there is a buried gumbo which, while it is 

 believed to represent merely an episode in Kansan hisiiory is 

 possibly susceptible to another interpretation.! Near Sigour- 

 ney, in Keokuk county, Mr. Leverett has noted an old soil in the 

 drift far outside the limits of both the lowan and the Illinoian. 



*Geol. Decatur Go , Iowa Geol. Sur., Vol. VI T. In press. 

 + Geol. Decatur Oouaty. 



