176 T. C. ■ II Wir.l i;l IX — THE INTERGLACIAL [NTERVAL. 



fl <i in depth. The upper pan of the silt becomes dirty in color, and at the 

 top there seeme to be a char demarkation from an upper silt. Thia dark, 

 Boil like band seemed to Professor Salisbury and myself to clearly indicate 

 an ancient Burface. Now, thai silt,in thai region at least, does not contain 

 any of the characteristic fossils at least they were not found by us : mo 

 far as we know, does it show any microscopic peculiarity which indicates its 

 origin. It remains with us an open question whether this belongs to the 

 glacial series or not Our prepossessions are strongly in the affirmative, be- 

 cause we have two formations at the north for which we wish to find equiva- 

 lents in thai southern region, namely, the lower till, to which I referred in 

 my paper, and the upper till, to which I also referred. We find further 

 north, in connection with each of these till>, loess-like surfaces, and have 

 been searching in the lower Mississippi valley for their equivalents. If we 

 find thai the lower Bill is glacial, we have what we Beek. The interval I 

 described was subsequent to the formation of both these silt series. You are 

 aware that Mr. McGee insists upon there being a long interval between the 

 two silts. I concede that But it seems to me that the later interval was 



eater than this. That is .-imply a point of difference of opinion. The 

 erosion measure 1 have described is applicable to the later interval. There 

 is no difference between us whatever as to the facts upon this point at least, 

 hut there i- a difference of interpretation. 



Mr. d. K. Procter: [n addition to the information derived from President 

 Chamberlin's paper, I have come to Borne knowledge of the (acts in regard 

 p. the "Orange Sand." My observations in western Kentucky and Mis- 



-ippi are that the pebbles of that deposit run up into the loess for four or 

 live feet, LT't i i dlt Bmalleras we rise above the horizon .,f the Orangi Sand. 

 I have found in the Orange Sand at Hickman, Columbus and Paducah 

 -ilieiiied fragments of the rock- of the Mississippi valley, as well a- Trenton 

 fossils, not very much worn. It i> mostly made up of pebbles and cherl 

 from the lower < larboniferous, and on the western holder we have islands of 

 chert, much worn down, in which the cherty fragments are angular and 

 sharp, and that same chert is found interstratified with the lime-tone.- on the 

 eastern border of thi si r< c< nt formations : but as we L r et nearer to the Mis- 

 sissippi river and further away from the Carboniferous rocks these angular 

 ami -harp cherts become more rounded and worn, and I believe that this 

 same ( 'range Sand deposit is traceable all the way up the Ohio river to the 

 mouth of the 1 1 3 indy, partaking more and more of the character of the 

 northern rock a- we go northward. I found the same deposil on Sandy 

 river, hut a- we gel into southern waters of thia and other Kentucky Btreama 

 we find in thi- gravel deposit (which is in the " second bottoms," or above 

 the high water of the river | no evidences of northern rocks. This i- true 

 the -ravel- of Kentucky river, the Sand} . and the Licking ; hut immediately 



