div class=ts-pagebutton class=gotoPage data-page=1Page 1button div class=ts-imageimg data-url=ha-2-1ogsouedudocshydrologicatlasesha2p1pdf-valleys-separated-by-narrowhtmlpage=1 data-page=1 class=ts-thumb lazyload alt=Page 1: HA 2 1ogsouedudocshydrologicatlasesHA2P1pdfvalleys separated by narrow flat-topped ridges Downcutting by Spring and Spavinaw Creeks and the Illinois River has exposed rocks loading=lazy src=data:imagegifbase64iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAQAAADYv8WvAAAAD0lEQVR42mP8X8AwAgiABKBAv+vAXklAAAAAElFTkSuQmCC data-src=https:reader033vdocumentsmxreader033viewer20220430015f7ca108637d16650a34c43dhtml5thumbnails1jpg width=140 height=200 divdiv