div class=ts-pagebutton class=gotoPage data-page=1Page 1button div class=ts-imageimg data-url=us-geological-survey-publications-warehouse-us-geol-survey-prof-paper-489htmlpage=1 data-page=1 class=ts-thumb lazyload alt=Page 1: US Geological Survey Publications WarehouseUS Geol Survey Prof Paper 489 109 p see reference 2 above modified by see reference 2 above modif i ed by F K - SLATE ÃORMHr01 loading=lazy src=data:imagegifbase64iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAQAAADYv8WvAAAAD0lEQVR42mP8X8AwAgiABKBAv+vAXklAAAAAElFTkSuQmCC data-src=https:reader035vdocumentsnetreader035viewer202208161760464d30573e5c57476ab322html5thumbnails1jpg width=140 height=200 divdiv