314 THWAITES AND TWENHOFEL THE WINDROW FORMATION 



(33) N. H. Winchell: Geology of Mower County. Geology of Minnesota. 



volume 1, 1884, pages 355-356. 



(34) A. H. WoRTHEN : Geological Survey of Illinois, volume 1, 1866, pages 829- 



330. 



(35) : Geological Survey of Illinois, volume 4, 1870, pages 37, 91, 179. 



