575:
545:
589:
765:... and the configuration of the lower surface indicates location of preexisting valleys and the most likely locale of earliest sedimentation. ... Therefore, it is expectable that the lowest, hence oldest, members be present in low areas of the bedrock, ... The relation of the configuration of the erosional surface at the base of the Ogallala to the stratigraphy of the formation has been fully recognized only recently (Merriam and Frye, 1954)
115:
745:.... It is quite clear ... that the bed belongs to the Ogallala and is the capping rock of the section. .... Frye (1945a) presented an hypothesis of "Algal limestone" formation in lakes that occupied consequent depressions and abandoned channel segments, after deposition had virtually ceased on the piedmont plain of alluviation that marked the top of the Ogallala deposits.
510:(oldest). Kansas geologists attempted to carry these classifications into the state; but, the state has since abandoned the three divisions. Like the remainder of High Plains states, Kansas considers the Ogallala to be a formation. However, it is convenient to informally divide the Ogallala into the three general zones with these names:
466:
caliche of the "Algal limestone" occurred broadly at the same time but in whatever material was at the local surface after deposition of the sand and gravel ceased. And, while the "Algal limestone" is a marker bed, it does not establish correlation of the specific beds in which the caliche formed.
465:
Other than the lower opaline sandstone zone and the "Algal limestone", the
Ogallala has no persistent lithological marker beds beyond the stated generalities of local chert beds in the upper zone and local caliche "mortar bed" lenses in the middle zone. It may be the case that consolidation of the
440:
under a shallow lake). However, the material is determined to be mostly caliche that formed after deposition of the sand and gravel from the mountain rivers was sharply reduced and the climate became arid or semiarid. This extensive and resistant material established the broad flat expanses of the
370:
was elevated several thousand feet (thousands of meters) above sea level. The pattern of erosion of material from the northeast into the midcontinent was largely reversed from the previous drainage patterns of the
Cretaceous and earlier periods so that material eroded from the Rocky Mountains was
453:
The lowest, oldest deposits filled in the shallow valleys of the weathered rocks that were exposed at that time, which ranged in age from
Cretaceous in Nebraska and Kansas to Permian in Texas. As the rivers built up the alluvial fans, subsurface water circulation varied, resulting in localized
779:
Hunt, ReBecca K., Vincent L. Santucci and Jason
Kenworthy. 2006. "A preliminary inventory of fossil fish from National Park Service units." in S.G. Lucas, J.A. Spielmann, P.M. Hester, J.P. Kenworthy, and V.L. Santucci (ed.s), Fossils from Federal Lands. New Mexico Museum of Natural History and
449:
overlies the
Ogallala in Texas and southwestern Kansas. Much of the underlying sand and gravel is unconsolidated or poorly consolidated such that it easily erodes away, leaving in western Kansas, Nebraska, and Texas a range of dramatic high bluffs that define the boundary of a "high plain".
420:
of sand and gravel, displaying bedding resulting from river flows and flooding. Much of this material remained unconsolidated; however, significant modification occurred as the material deepened, particularly with the cementation of the sand and gravel with
544:
494:
basis. The
Ogallala's rich grass seed record was also used to develop biostratigraphic successions within the unit. Unfortunately, no correlation with any consistent rock bedding can be established over the Ogallala's range.
2731:
1876:
1343:
847:
454:
formation of caliche, and shallow lakes formed between natural levees, which deposited limestone. These consolidated lenses, distributed in within the middle portion, do not represent any particular
390:
Many rivers carried this material from the mountains to the east. What each river carried from different parts of the mountains varied, changing also as the geography of the Rocky
Mountains evolved.
458:; but do cap intermediate bluffs below valley rims. Because of their bluff-forming nature and resemblance to concrete or mortar, these lenses are described as "caprock" or "mortar beds". Various
805:
2898:
602:
2717:
1862:
436:, broadly called "algal limestone". Patterns of thin lines in the "limestone" suggested algal origin to frontier geologists (calcite and silica deposited within mats of
1329:
833:
798:
347:
2883:
791:
343:
2724:
1869:
2878:
2873:
1336:
840:
2893:
2888:
462:
were locally deposited, supplying silica for the formation of agate and chert in the upper portion and opal in the lowest portion.
124:
474:
Faced with particularly rich collections of terrestrial
Neogene vertebrate fossils, Nebraska geologists recognized the distinct
475:
363:
324:
371:
carried eastward on to expansive, geologically weathered plains. This material included quartz and feldspar from
393:
Owing to the low amount of sloping, vast quantities of sand and gravel were dumped on the plains in broad and overlapping
2863:
400:
Over this time, many volcanic ash falls occurred and have been identified to their source, including several from the
304:
254:
1304:
689:"A Review of the Stratigraphy of the Ogallala Formation and Revision of Neogene ("Tertiary") Nomenclature in Kansas"
2868:
2282:
2100:
1426:
2115:
1516:
1123:
2419:
2370:
2318:
2242:
1299:
1018:
607:
300:
135:
1033:
2015:
1609:
2340:
2222:
2174:
2120:
1546:
1526:
1200:
1160:
1070:
1058:
367:
2467:
2020:
2005:
1670:
1486:
1406:
1232:
2447:
2292:
2227:
2090:
1568:
1563:
1277:
1028:
498:
These
Nebraskan biostratigraphic classifications elevated the Ogallala to group status with three members
2345:
2055:
2025:
1466:
1180:
1023:
977:
941:
2834:
2564:
2262:
2247:
2217:
2150:
1536:
1411:
1267:
1252:
1195:
1138:
1048:
1013:
763:. University of Kansas Publications, State Geological Survey of Kansas. p. Methods of Correlation.
743:. University of Kansas Publications, State Geological Survey of Kansas. p. Methods of Correlation.
580:
2818:
2569:
2524:
2497:
2462:
2452:
2360:
2145:
2110:
2065:
2035:
1451:
1133:
514:
499:
152:
2688:
2683:
2661:
2625:
2335:
2330:
2252:
2232:
2212:
2125:
2085:
2040:
2030:
1948:
1943:
1816:
1811:
2780:
2355:
2257:
2140:
2095:
2080:
1481:
1456:
1446:
1257:
1247:
1143:
1053:
1038:
520:
503:
158:
139:
2792:
1647:
1642:
1511:
687:
Greg A. Ludvigson; Robert S. Sawin; Evan K. Franseen; W. Lynn Watney; Ronald R. West; Jon J. Smith.
2365:
2302:
2130:
1938:
1806:
1789:
1745:
1436:
1431:
1262:
594:
526:
507:
401:
338:. It also includes an excellent record of grass seeds and other plant seeds, which can be used for
163:
2190:
2045:
1978:
1829:
1763:
1652:
1604:
1506:
1461:
1282:
1272:
1190:
1185:
1170:
1106:
1043:
1000:
814:
721:
375:
granite, but also residue from the uplifted shale, limestone, and sandstone accumulated from the
279:
758:
738:
655:
2666:
2644:
2630:
2608:
2601:
2551:
2519:
2511:
2272:
2237:
2105:
2050:
1685:
1675:
1637:
1614:
1541:
1496:
1476:
1416:
1237:
1210:
1165:
1128:
901:
455:
422:
2802:
2534:
2490:
2442:
2375:
2287:
2267:
2195:
2075:
2060:
2000:
1983:
1718:
1680:
1632:
1599:
1555:
1531:
1396:
1389:
1242:
1227:
555:
446:
308:
554:, TX, showing the locally red-colored Ogallala Formation and the bright white color of the
2502:
2457:
2432:
2350:
2277:
2207:
2135:
2070:
2010:
1728:
1624:
1471:
1205:
1118:
491:
426:
339:
708:"Lake Meredith National Recreation Area," Hunt, Santucci, and Kenworthy (2006); page 67.
637:
2764:
2437:
2402:
2155:
1773:
1758:
1710:
1662:
1591:
1441:
992:
405:
2857:
2165:
1931:
1401:
1175:
612:
551:
264:
73:
38:
1521:
1491:
1421:
479:
459:
441:
High Plains. Most of the material that overlies this bed is wind-blown
Pleistocene
417:
394:
331:
316:
239:
114:
693:
Kansas Geological Survey, Current Research in Earth Sciences, Bulletin 256, Part 2
783:
760:
Stratigraphy of the Ogallala Formation (Neogene) of Northern Kansas, Bulletin 118
740:
Stratigraphy of the Ogallala Formation (Neogene) of Northern Kansas, Bulletin 118
2755:
2746:
2543:
2311:
1891:
1501:
1358:
893:
862:
688:
483:
372:
327:
176:
48:
2653:
2481:
1961:
1380:
884:
636:
Rex C. Buchanan; B. Brownie Wilson; Robert R. Buddemeier; James J. Butler Jr.
570:
335:
190:
93:
58:
17:
2592:
2411:
1922:
1902:
1782:
1219:
1090:
1079:
969:
432:
The top of the Ogallala is defined by a thick cap rock of hard limestone or
376:
235:
98:
2811:
2583:
2393:
2183:
1970:
1699:
1582:
1369:
1099:
933:
924:
873:
818:
384:
380:
346:
preserve fish fossils. Similar specimens from the same unit are found at
312:
296:
198:
194:
88:
83:
68:
63:
53:
2617:
1913:
1737:
960:
915:
487:
433:
292:
219:
202:
120:
103:
78:
2773:
1798:
1153:
662:. Geolex — Significant Publications. United States Geological Survey
517:- the upper zone with the "Algal limestone", agate, and chert beds
442:
437:
351:
179:
523:- the broad middle zone with the additional caprock "mortar beds"
342:
dating within the formation. The Ogallala Formation outcrops of
231:
2713:
1858:
1325:
829:
787:
642:
Kansas Geological Survey, Public Information Circular (PIC) 18
416:
From bottom to top, the Ogallala was deposited as overlapping
397:
rather than being carried into the Mississippi River.
757:
John C. Frye; A. Byron Leonard; Ada Swineford (1956).
737:
John C. Frye; A. Byron Leonard; Ada Swineford (1956).
704:
702:
603:
List of fossiliferous stratigraphic units in Nebraska
490:
sufficient to attempt definitions of formations on a
307:
of the western United States and the location of the
2810:
2801:
2772:
2763:
2754:
2745:
2652:
2643:
2616:
2600:
2591:
2582:
2542:
2533:
2510:
2489:
2480:
2410:
2401:
2392:
2310:
2301:
2182:
2173:
2164:
1969:
1960:
1930:
1921:
1912:
1901:
1890:
1797:
1781:
1772:
1736:
1727:
1709:
1698:
1661:
1623:
1590:
1581:
1554:
1388:
1379:
1368:
1357:
1218:
1152:
1098:
1089:
1078:
991:
968:
959:
932:
923:
914:
892:
883:
872:
861:
726:, updated version without Ogallala divisions, 2018
275:
270:
260:
250:
245:
226:
214:
209:
185:
172:
145:
131:
32:
682:
680:
678:
676:
27:Geologic formation in the western United States
2725:
1870:
1337:
841:
799:
8:
2899:Neogene stratigraphic units of North America
529:- the lowest zone with the opaline sandstone
2807:
2769:
2760:
2751:
2740:Precambrian chronostratigraphy of Colorado
2732:
2718:
2710:
2649:
2597:
2588:
2539:
2486:
2407:
2398:
2307:
2179:
2170:
1966:
1927:
1918:
1909:
1898:
1877:
1863:
1855:
1778:
1733:
1706:
1587:
1385:
1376:
1365:
1344:
1330:
1322:
1095:
1086:
965:
929:
920:
889:
880:
869:
848:
834:
826:
806:
792:
784:
113:
29:
716:
714:
348:Alibates Flint Quarries National Monument
1885:Paleozoic chronostratigraphy of Colorado
325:North American Land Mammal Ages (NALMAs)
123:beds from the middle of the Ogallala at
1352:Mesozoic chronostratigraphy of Colorado
856:Cenozoic chronostratigraphy of Colorado
628:
540:
723:The Stratigraphic Succession in Kansas
383:periods, as well as igneous rock from
344:Lake Meredith National Recreation Area
7:
780:Science Bulletin 34, pp. 63–69.
119:Common appearance of the "caprock"
25:
230:chert, agate, opaline sandstone,
587:
573:
543:
2884:Neogene geology of South Dakota
1305:Independence Mountain Formation
476:North American land mammal ages
1:
2283:Morgan Round Valley Formation
478:(NALMA) within the Ogallala;
319:it is also classified as the
2116:South Canyon Creek Formation
2879:Neogene geology of Oklahoma
2874:Neogene geology of Nebraska
2915:
2894:Neogene geology of Wyoming
2101:Sangre de Cristo Formation
1124:Central Colorado Volcanics
660:National Geologic Database
323:. Notably, it records the
2709:
2420:Williams Canyon Formation
2326:
2319:Williams Canyon Formation
2243:Jacque Mountain Formation
1854:
1517:Pictured Cliffs Formation
1321:
1300:Gravel Mountain Formation
825:
656:"Geologic Unit: Ogallala"
638:"The High Plains Aquifer"
366:, the final floor of the
112:
37:
2889:Neogene geology of Texas
2371:Ste. Genevieve Formation
1034:Martins Canyon Formation
1019:Cedar Mountain Formation
608:Paleontology in Nebraska
402:Yellowstone Supervolcano
362:At the beginning of the
2016:Council Grove Formation
1610:Ralston Creek Formation
1547:Williams Fork Formation
1527:Point Lookout Formation
1201:Poison Canyon Formation
404: and two from the
368:Western Interior Seaway
2341:Headscrabble Formation
2223:Eagle Valley Evaporite
2121:Stone Corral Formation
1564:Burro Canyon Formation
1161:Blanco Basin Formation
1071:Grouse Mountain Basalt
1059:Wagon Tongue Formation
364:Rocky Mountains uplift
44:Miocene–Early Pliocene
2835:Uncompahgre Formation
2468:Pinyon Park Formation
2248:Kansas City Formation
2021:Crestone Conglomerate
2006:Cedar Hills Formation
1671:Glen Canyon Formation
1487:Lion Canyon Formation
1412:Cliff House Sandstone
1407:Castle Gate Formation
1253:Middle Park Formation
1233:Arapahoe Conglomerate
1196:Green River Formation
1049:Troublesome Formation
1014:Browns Park Formation
581:Earth sciences portal
2781:Uinta Mountain Group
2448:Kinderhook Formation
2293:Sharpsdale Formation
2228:Glen Eyrie Formation
2141:Wellington Formation
2096:Phosphoria Formation
2091:Owl Canyon Formation
2081:Minnekahta Formation
1569:Horsetooth Formation
1278:South Park Formation
1258:Nacimiento Formation
1248:Fort Union Formation
1039:North Park Formation
1029:Los Pintos Formation
125:Ash Hollow, Nebraska
2864:Geology of Colorado
2366:St. Louis Formation
2346:Leadville Formation
2131:Wabaunsee Formation
2056:Ingleside Formation
2026:Day Creek Formation
1939:Chugwater Formation
1807:Chugwater Formation
1790:Chugwater Formation
1746:Chugwater Formation
1467:Kremmling Formation
1437:Fruitland Formation
1432:Fox Hills Formation
1427:Fort Hays Limestone
1263:Ojo Alamo Formation
1181:Echo Park Formation
1024:Flat Tops Volcanics
978:Dry Union Formation
942:Dry Union Formation
595:Paleontology portal
39:Stratigraphic range
2565:Arbuckle Formation
2263:Marmaton Formation
2218:Cherokee Formation
2191:Fountain Formation
2151:Wolfcamp Formation
2046:Glorieta Formation
1979:Fountain Formation
1830:Moenkopi Formation
1764:Moenkopi Formation
1653:Sundance Formation
1605:Morrison Formation
1537:Trinidad Formation
1507:Niobrara Formation
1462:Kirtland Formation
1283:Washakie Formation
1273:San Jose Formation
1268:Raton Conglomerate
1191:Huerfano Formation
1186:Farisita Formation
1139:Pinnacle Formation
1107:Arikaree Formation
1044:Santa Fe Formation
1001:Arikaree Formation
983:Ogallala Formation
947:Ogallala Formation
815:Chronostratigraphy
289:Ogallala Formation
280:Ogallala, Nebraska
33:Ogallala Formation
2869:Geology of Kansas
2851:
2850:
2847:
2846:
2843:
2842:
2830:
2829:
2826:
2825:
2819:Owiyukuts Complex
2788:
2787:
2705:
2704:
2701:
2700:
2697:
2696:
2679:
2678:
2675:
2674:
2667:Sawatch Formation
2639:
2638:
2631:Sawatch Formation
2609:Dotsero Formation
2578:
2577:
2570:Manitou Formation
2560:
2559:
2552:Dotsero Formation
2525:Simpson Formation
2520:Harding Sandstone
2498:Fremont Limestone
2476:
2475:
2463:Parting Formation
2453:Misener Formation
2428:
2427:
2388:
2387:
2384:
2383:
2361:Spergen Formation
2273:Minturn Formation
2238:Hermosa Formation
2203:
2202:
2146:White Horse Group
2111:Shawnee Formation
2106:Satanka Formation
2066:Lansing Formation
2051:Hermosa Formation
2036:Forelle Formation
1996:
1995:
1992:
1991:
1956:
1955:
1850:
1849:
1846:
1845:
1842:
1841:
1838:
1837:
1825:
1824:
1754:
1753:
1694:
1693:
1686:Wingate Sandstone
1676:Kayenta Formation
1638:Entrada Formation
1615:Wanakah Formation
1577:
1576:
1542:Vermejo Formation
1497:Menefee Formation
1477:Laramie Formation
1452:Hygiene Formation
1317:
1316:
1313:
1312:
1295:
1294:
1291:
1290:
1238:Bridger Formation
1211:Wasatch Formation
1166:Cuchara Formation
1134:Conejos Formation
1129:Chadron Formation
1114:
1113:
1067:
1066:
1009:
1008:
955:
954:
910:
909:
902:Alamosa Formation
423:calcium carbonate
412:Lithostratigraphy
285:
284:
16:(Redirected from
2906:
2808:
2770:
2761:
2752:
2734:
2727:
2720:
2711:
2689:Tintic Formation
2684:Reagan Formation
2662:Lodore Formation
2650:
2626:Lodore Formation
2598:
2589:
2540:
2487:
2443:Elbert Formation
2408:
2399:
2376:Warsaw Formation
2336:Gilman Formation
2331:Beulah Formation
2308:
2288:Morrow Formation
2268:Maroon Formation
2253:Kerber Formation
2233:Gothic Formation
2213:Belden Formation
2196:Madera Formation
2180:
2171:
2126:Sumner Formation
2086:Opeche Formation
2076:Maroon Formation
2061:Kaibab Limestone
2041:Glendo Formation
2031:Falcon Formation
2001:Blaine Formation
1984:Madera Formation
1967:
1949:Taloga Formation
1944:Lykins Formation
1928:
1919:
1910:
1905:
1899:
1894:
1879:
1872:
1865:
1856:
1817:Taloga Formation
1812:Lykins Formation
1779:
1734:
1719:Chinle Formation
1707:
1702:
1681:Navajo Formation
1633:Carmel Formation
1600:Curtis Formation
1588:
1532:Smoky Hill Chalk
1417:Codell Sandstone
1397:Benton Formation
1386:
1377:
1372:
1366:
1361:
1346:
1339:
1332:
1323:
1243:Denver Formation
1228:Animas Formation
1096:
1087:
1082:
966:
930:
921:
890:
881:
876:
870:
865:
850:
843:
836:
827:
808:
801:
794:
785:
768:
767:
754:
748:
747:
734:
728:
727:
718:
709:
706:
697:
696:
684:
671:
670:
668:
667:
652:
646:
645:
633:
597:
592:
591:
590:
583:
578:
577:
576:
556:Blanco Formation
547:
492:biostratigraphic
447:Blanco Formation
340:biostratigraphic
309:Ogallala Aquifer
117:
108:
45:
30:
21:
2914:
2913:
2909:
2908:
2907:
2905:
2904:
2903:
2854:
2853:
2852:
2839:
2822:
2797:
2784:
2741:
2738:
2693:
2671:
2635:
2612:
2574:
2556:
2529:
2506:
2503:Viola Formation
2472:
2458:Ouray Formation
2433:Aneth Formation
2424:
2380:
2356:Osage Formation
2351:Molas Formation
2322:
2297:
2278:Molas Formation
2258:Keyes Formation
2208:Atoka Formation
2199:
2160:
2136:Weber Formation
2071:Lyons Formation
2011:Chase Formation
1988:
1952:
1903:
1892:
1886:
1883:
1834:
1821:
1793:
1768:
1750:
1723:
1700:
1690:
1657:
1619:
1573:
1550:
1482:Lewis Formation
1472:Lance Formation
1447:Greenhorn Shale
1370:
1359:
1353:
1350:
1309:
1287:
1214:
1206:Uinta Formation
1148:
1144:Pitch Formation
1119:Brule Formation
1110:
1080:
1074:
1063:
1054:Trump Formation
1005:
987:
951:
906:
874:
863:
857:
854:
821:
812:
771:
756:
755:
751:
736:
735:
731:
720:
719:
712:
707:
700:
686:
685:
674:
665:
663:
654:
653:
649:
635:
634:
630:
621:
593:
588:
586:
579:
574:
572:
569:
564:
563:
562:
559:
548:
536:
472:
470:Biostratigraphy
414:
360:
303:in the central
149:Nebraska only:
127:
107:
106:
101:
96:
91:
86:
81:
76:
71:
66:
61:
56:
51:
43:
42:
28:
23:
22:
15:
12:
11:
5:
2912:
2910:
2902:
2901:
2896:
2891:
2886:
2881:
2876:
2871:
2866:
2856:
2855:
2849:
2848:
2845:
2844:
2841:
2840:
2838:
2837:
2831:
2828:
2827:
2824:
2823:
2821:
2816:
2814:
2805:
2799:
2798:
2796:
2795:
2793:Tava Formation
2789:
2786:
2785:
2783:
2778:
2776:
2767:
2758:
2749:
2743:
2742:
2739:
2737:
2736:
2729:
2722:
2714:
2707:
2706:
2703:
2702:
2699:
2698:
2695:
2694:
2692:
2691:
2686:
2680:
2677:
2676:
2673:
2672:
2670:
2669:
2664:
2658:
2656:
2647:
2641:
2640:
2637:
2636:
2634:
2633:
2628:
2622:
2620:
2614:
2613:
2611:
2606:
2604:
2595:
2586:
2580:
2579:
2576:
2575:
2573:
2572:
2567:
2561:
2558:
2557:
2555:
2554:
2548:
2546:
2537:
2531:
2530:
2528:
2527:
2522:
2516:
2514:
2508:
2507:
2505:
2500:
2495:
2493:
2484:
2478:
2477:
2474:
2473:
2471:
2470:
2465:
2460:
2455:
2450:
2445:
2440:
2438:Dyer Formation
2435:
2429:
2426:
2425:
2423:
2422:
2416:
2414:
2405:
2396:
2390:
2389:
2386:
2385:
2382:
2381:
2379:
2378:
2373:
2368:
2363:
2358:
2353:
2348:
2343:
2338:
2333:
2327:
2324:
2323:
2321:
2316:
2314:
2305:
2299:
2298:
2296:
2295:
2290:
2285:
2280:
2275:
2270:
2265:
2260:
2255:
2250:
2245:
2240:
2235:
2230:
2225:
2220:
2215:
2210:
2204:
2201:
2200:
2198:
2193:
2188:
2186:
2177:
2168:
2162:
2161:
2159:
2158:
2156:Yeso Formation
2153:
2148:
2143:
2138:
2133:
2128:
2123:
2118:
2113:
2108:
2103:
2098:
2093:
2088:
2083:
2078:
2073:
2068:
2063:
2058:
2053:
2048:
2043:
2038:
2033:
2028:
2023:
2018:
2013:
2008:
2003:
1997:
1994:
1993:
1990:
1989:
1987:
1986:
1981:
1975:
1973:
1964:
1958:
1957:
1954:
1953:
1951:
1946:
1941:
1936:
1934:
1925:
1916:
1907:
1896:
1888:
1887:
1884:
1882:
1881:
1874:
1867:
1859:
1852:
1851:
1848:
1847:
1844:
1843:
1840:
1839:
1836:
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1833:
1832:
1826:
1823:
1822:
1820:
1819:
1814:
1809:
1803:
1801:
1795:
1794:
1792:
1787:
1785:
1776:
1770:
1769:
1767:
1766:
1761:
1759:Jelm Formation
1755:
1752:
1751:
1749:
1748:
1742:
1740:
1731:
1725:
1724:
1722:
1721:
1715:
1713:
1704:
1696:
1695:
1692:
1691:
1689:
1688:
1683:
1678:
1673:
1667:
1665:
1659:
1658:
1656:
1655:
1650:
1648:Page Formation
1645:
1643:Garo Formation
1640:
1635:
1629:
1627:
1621:
1620:
1618:
1617:
1612:
1607:
1602:
1596:
1594:
1585:
1579:
1578:
1575:
1574:
1572:
1571:
1566:
1560:
1558:
1552:
1551:
1549:
1544:
1539:
1534:
1529:
1524:
1519:
1514:
1512:Pando Porphyry
1509:
1504:
1499:
1494:
1489:
1484:
1479:
1474:
1469:
1464:
1459:
1454:
1449:
1444:
1442:Graneros Shale
1439:
1434:
1429:
1424:
1419:
1414:
1409:
1404:
1399:
1394:
1392:
1383:
1374:
1363:
1355:
1354:
1351:
1349:
1348:
1341:
1334:
1326:
1319:
1318:
1315:
1314:
1311:
1310:
1308:
1307:
1302:
1296:
1293:
1292:
1289:
1288:
1286:
1285:
1280:
1275:
1270:
1265:
1260:
1255:
1250:
1245:
1240:
1235:
1230:
1224:
1222:
1216:
1215:
1213:
1208:
1203:
1198:
1193:
1188:
1183:
1178:
1173:
1168:
1163:
1158:
1156:
1150:
1149:
1147:
1146:
1141:
1136:
1131:
1126:
1121:
1115:
1112:
1111:
1109:
1104:
1102:
1093:
1084:
1076:
1075:
1073:
1068:
1065:
1064:
1062:
1061:
1056:
1051:
1046:
1041:
1036:
1031:
1026:
1021:
1016:
1010:
1007:
1006:
1004:
1003:
997:
995:
989:
988:
986:
985:
980:
974:
972:
963:
957:
956:
953:
952:
950:
949:
944:
938:
936:
927:
918:
912:
911:
908:
907:
905:
904:
898:
896:
887:
878:
867:
859:
858:
855:
853:
852:
845:
838:
830:
823:
822:
813:
811:
810:
803:
796:
788:
782:
781:
776:
775:
770:
769:
749:
729:
710:
698:
672:
647:
627:
626:
625:
620:
617:
616:
615:
610:
605:
599:
598:
584:
568:
565:
561:
560:
549:
542:
539:
538:
537:
535:
532:
531:
530:
524:
518:
471:
468:
413:
410:
359:
356:
321:Ogallala Group
283:
282:
277:
273:
272:
268:
267:
262:
258:
257:
252:
248:
247:
243:
242:
228:
224:
223:
218:sand, gravel,
216:
212:
211:
207:
206:
187:
183:
182:
174:
170:
169:
168:
167:
161:
156:
147:
143:
142:
133:
129:
128:
118:
110:
109:
102:
97:
92:
87:
82:
77:
72:
67:
62:
57:
52:
47:
46:
35:
34:
26:
24:
18:Ogallala Group
14:
13:
10:
9:
6:
4:
3:
2:
2911:
2900:
2897:
2895:
2892:
2890:
2887:
2885:
2882:
2880:
2877:
2875:
2872:
2870:
2867:
2865:
2862:
2861:
2859:
2836:
2833:
2832:
2820:
2817:
2815:
2813:
2809:
2806:
2804:
2800:
2794:
2791:
2790:
2782:
2779:
2777:
2775:
2771:
2768:
2766:
2762:
2759:
2757:
2753:
2750:
2748:
2744:
2735:
2730:
2728:
2723:
2721:
2716:
2715:
2712:
2708:
2690:
2687:
2685:
2682:
2681:
2668:
2665:
2663:
2660:
2659:
2657:
2655:
2651:
2648:
2646:
2642:
2632:
2629:
2627:
2624:
2623:
2621:
2619:
2615:
2610:
2607:
2605:
2603:
2599:
2596:
2594:
2590:
2587:
2585:
2581:
2571:
2568:
2566:
2563:
2562:
2553:
2550:
2549:
2547:
2545:
2541:
2538:
2536:
2532:
2526:
2523:
2521:
2518:
2517:
2515:
2513:
2509:
2504:
2501:
2499:
2496:
2494:
2492:
2488:
2485:
2483:
2479:
2469:
2466:
2464:
2461:
2459:
2456:
2454:
2451:
2449:
2446:
2444:
2441:
2439:
2436:
2434:
2431:
2430:
2421:
2418:
2417:
2415:
2413:
2409:
2406:
2404:
2400:
2397:
2395:
2391:
2377:
2374:
2372:
2369:
2367:
2364:
2362:
2359:
2357:
2354:
2352:
2349:
2347:
2344:
2342:
2339:
2337:
2334:
2332:
2329:
2328:
2325:
2320:
2317:
2315:
2313:
2309:
2306:
2304:
2300:
2294:
2291:
2289:
2286:
2284:
2281:
2279:
2276:
2274:
2271:
2269:
2266:
2264:
2261:
2259:
2256:
2254:
2251:
2249:
2246:
2244:
2241:
2239:
2236:
2234:
2231:
2229:
2226:
2224:
2221:
2219:
2216:
2214:
2211:
2209:
2206:
2205:
2197:
2194:
2192:
2189:
2187:
2185:
2181:
2178:
2176:
2172:
2169:
2167:
2163:
2157:
2154:
2152:
2149:
2147:
2144:
2142:
2139:
2137:
2134:
2132:
2129:
2127:
2124:
2122:
2119:
2117:
2114:
2112:
2109:
2107:
2104:
2102:
2099:
2097:
2094:
2092:
2089:
2087:
2084:
2082:
2079:
2077:
2074:
2072:
2069:
2067:
2064:
2062:
2059:
2057:
2054:
2052:
2049:
2047:
2044:
2042:
2039:
2037:
2034:
2032:
2029:
2027:
2024:
2022:
2019:
2017:
2014:
2012:
2009:
2007:
2004:
2002:
1999:
1998:
1985:
1982:
1980:
1977:
1976:
1974:
1972:
1968:
1965:
1963:
1959:
1950:
1947:
1945:
1942:
1940:
1937:
1935:
1933:
1932:Changhsingian
1929:
1926:
1924:
1920:
1917:
1915:
1911:
1908:
1906:
1900:
1897:
1895:
1889:
1880:
1875:
1873:
1868:
1866:
1861:
1860:
1857:
1853:
1831:
1828:
1827:
1818:
1815:
1813:
1810:
1808:
1805:
1804:
1802:
1800:
1796:
1791:
1788:
1786:
1784:
1780:
1777:
1775:
1771:
1765:
1762:
1760:
1757:
1756:
1747:
1744:
1743:
1741:
1739:
1735:
1732:
1730:
1726:
1720:
1717:
1716:
1714:
1712:
1708:
1705:
1703:
1697:
1687:
1684:
1682:
1679:
1677:
1674:
1672:
1669:
1668:
1666:
1664:
1660:
1654:
1651:
1649:
1646:
1644:
1641:
1639:
1636:
1634:
1631:
1630:
1628:
1626:
1622:
1616:
1613:
1611:
1608:
1606:
1603:
1601:
1598:
1597:
1595:
1593:
1589:
1586:
1584:
1580:
1570:
1567:
1565:
1562:
1561:
1559:
1557:
1553:
1548:
1545:
1543:
1540:
1538:
1535:
1533:
1530:
1528:
1525:
1523:
1520:
1518:
1515:
1513:
1510:
1508:
1505:
1503:
1500:
1498:
1495:
1493:
1490:
1488:
1485:
1483:
1480:
1478:
1475:
1473:
1470:
1468:
1465:
1463:
1460:
1458:
1455:
1453:
1450:
1448:
1445:
1443:
1440:
1438:
1435:
1433:
1430:
1428:
1425:
1423:
1420:
1418:
1415:
1413:
1410:
1408:
1405:
1403:
1402:Carlile Shale
1400:
1398:
1395:
1393:
1391:
1387:
1384:
1382:
1378:
1375:
1373:
1367:
1364:
1362:
1356:
1347:
1342:
1340:
1335:
1333:
1328:
1327:
1324:
1320:
1306:
1303:
1301:
1298:
1297:
1284:
1281:
1279:
1276:
1274:
1271:
1269:
1266:
1264:
1261:
1259:
1256:
1254:
1251:
1249:
1246:
1244:
1241:
1239:
1236:
1234:
1231:
1229:
1226:
1225:
1223:
1221:
1217:
1212:
1209:
1207:
1204:
1202:
1199:
1197:
1194:
1192:
1189:
1187:
1184:
1182:
1179:
1177:
1176:Dawson Arkose
1174:
1172:
1169:
1167:
1164:
1162:
1159:
1157:
1155:
1151:
1145:
1142:
1140:
1137:
1135:
1132:
1130:
1127:
1125:
1122:
1120:
1117:
1116:
1108:
1105:
1103:
1101:
1097:
1094:
1092:
1088:
1085:
1083:
1077:
1072:
1069:
1060:
1057:
1055:
1052:
1050:
1047:
1045:
1042:
1040:
1037:
1035:
1032:
1030:
1027:
1025:
1022:
1020:
1017:
1015:
1012:
1011:
1002:
999:
998:
996:
994:
990:
984:
981:
979:
976:
975:
973:
971:
967:
964:
962:
958:
948:
945:
943:
940:
939:
937:
935:
931:
928:
926:
922:
919:
917:
913:
903:
900:
899:
897:
895:
891:
888:
886:
882:
879:
877:
871:
868:
866:
860:
851:
846:
844:
839:
837:
832:
831:
828:
824:
820:
816:
809:
804:
802:
797:
795:
790:
789:
786:
778:
777:
773:
772:
766:
762:
761:
753:
750:
746:
742:
741:
733:
730:
725:
724:
717:
715:
711:
705:
703:
699:
694:
690:
683:
681:
679:
677:
673:
661:
657:
651:
648:
643:
639:
632:
629:
623:
622:
618:
614:
613:Blanco Canyon
611:
609:
606:
604:
601:
600:
596:
585:
582:
571:
566:
557:
553:
552:Blanco Canyon
550:East side of
546:
541:
533:
528:
525:
522:
519:
516:
513:
512:
511:
509:
505:
501:
496:
493:
489:
485:
481:
477:
469:
467:
463:
461:
457:
451:
448:
444:
439:
435:
430:
428:
424:
419:
418:alluvial fans
411:
409:
407:
406:Jemez Caldera
403:
398:
396:
395:alluvial fans
391:
388:
386:
382:
378:
374:
369:
365:
357:
355:
353:
349:
345:
341:
337:
333:
329:
326:
322:
318:
314:
310:
306:
302:
298:
294:
290:
281:
278:
274:
269:
266:
265:United States
263:
259:
256:
253:
249:
244:
241:
237:
233:
229:
225:
221:
217:
213:
208:
204:
200:
196:
192:
188:
184:
181:
178:
175:
171:
165:
162:
160:
157:
154:
151:
150:
148:
144:
141:
137:
134:
130:
126:
122:
116:
111:
105:
100:
95:
90:
85:
80:
75:
70:
65:
60:
55:
50:
40:
36:
31:
19:
1522:Pierre Shale
1492:Mancos Shale
1422:Dakota Group
982:
946:
764:
759:
752:
744:
739:
732:
722:
692:
664:. Retrieved
659:
650:
641:
631:
502:(youngest),
497:
480:Clarendonian
473:
464:
452:
445:, while the
431:
415:
399:
392:
389:
361:
332:Clarendonian
320:
317:South Dakota
288:
286:
271:Type section
2544:Tremadocian
2312:Tournaisian
1502:Mowry Shale
1457:Juana Lopez
1171:D2 Sequence
894:Pleistocene
484:Hemphillian
387:volcanism.
373:Precambrian
358:Development
328:Hemphillian
305:High Plains
255:High Plains
222:cementation
177:Pleistocene
2858:Categories
2654:Guzhangian
1962:Cisuralian
993:Aquitanian
666:2020-06-05
619:References
521:Ash Hollow
504:Ash Hollow
336:Barstovian
191:Cretaceous
189:Weathered
159:Ash Hollow
155:(youngest)
2593:Furongian
2412:Famennian
1923:Lopingian
1783:Olenekian
1220:Paleocene
1091:Oligocene
970:Messinian
624:Footnotes
527:Valentine
508:Valentine
460:ash falls
377:Paleozoic
301:formation
299:geologic
295:to early
276:Named for
236:limestone
210:Lithology
173:Underlies
164:Valentine
146:Sub-units
136:Formation
2812:Siderian
2645:Series 3
2602:Stage 10
2184:Gzhelian
1971:Asselian
1100:Chattian
934:Zanclean
925:Pliocene
819:Colorado
567:See also
385:Cenozoic
381:Mesozoic
313:Nebraska
297:Pliocene
246:Location
205:terrains
199:Triassic
195:Jurassic
186:Overlies
166:(oldest)
2618:Paibian
1738:Anisian
961:Miocene
774:Sources
534:Gallery
515:Kimball
500:Kimball
488:Blancan
456:horizon
434:caliche
293:Miocene
261:Country
220:caliche
215:Primary
203:Permian
153:Kimball
121:caliche
2774:Tonian
2512:Middle
1799:Induan
1729:Middle
1625:Middle
1154:Eocene
506:, and
486:, and
427:silica
334:, and
251:Region
201:, and
2535:Lower
2491:Upper
2403:Upper
1774:Lower
1711:Upper
1663:Lower
1592:Upper
1556:Lower
1390:Upper
443:loess
438:algae
352:Texas
311:. In
291:is a
227:Other
180:loess
140:Group
425:and
379:and
315:and
287:The
232:marl
132:Type
49:PreꞒ
817:of
350:in
240:ash
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