Surficial Geology of the Naper 7.5 Minute Quadrangle, Portion

R.M. Joeckel1, S.T. Tucker2, L.M. Howard1 and M.S. Kuzila1 1Conservation and Survey Division, University of Nebraska-Lincoln 2Highway Paleontology Program, University of Nebraska State Museum, University of Nebraska-Lincoln Kp Pierre Shale (Upper Cretaceous, Campanian-Maastrichtian) Qakp2 Young Quaternary alluvium of the Keya Paha River (Late Holocene) Qapc4 Older Quaternary alluvium of Ponca Creek (Holocene) Overview of the Nebraska Portion of the Naper Quadrangle

Version 1.0, September 2013 Gray to dark gray (weathering light gray, olive gray, olive brown, grayish brown, pale brown, Very pale brown, pale brown, brownish gray, and grayish brown, well-sorted very fine sand and Gray, light brownish gray, very pale brown, and brown sandy silt, silty fine sand and fine to Geographic Setting and Geomorphology

and pale yellow) silt shale to clay shale, with rare, very thin to thin beds of siltstone, very fine silty very fine sand. coarse sand. sandstone, and bentonite, as well as some beds of chalky limestone. The Naper Quadrangle lies almost entirely within northern Boyd County, Nebraska (a very small 99°07'30" 490000mE 491 492 493 5' 494 495 496 2'30" 497 498 0499 99°00' These deposits are associated in most places with visible meander scrolls and flood channels. Areas mapped as Qapc4 are comparatively smooth-surfaced and have been in long-term part of it lies within Gregory County in southern ). Only that portion of the 43°00' 43°00' The Pierre Shale is mapped on the slopes of the river valleys. Approximately 200 ft (61 m) of Most areas mapped at Qakp2 were wooded in the late 1930s and remain at least partially wooded agricultural use (likely more than a century). These areas probably never experience overbank quadrangle lying in Nebraska is presented as a geologic map in this document. T. 95 N. T. 95 N. GREGORY CO SOUTH DAKOTA GREGORY CO flooding. Since the entrenchment of Ponca Creek, these deposits are now part of one or more 1 upper Pierre Shale strata underlie the north valley wall of the Keya Paha River. These steep today, indicating that these areas have been stable for several dec ades at minimum. Areas 8 BOYD CO 1 5 9 NEBRASKA BOYD CO T. 35 N. T. 35 N. 5 0 0 alluvial terraces. The Naper Quadrangle lies southward and westward of the Laurentide glacial limit, on the Nov slopes are prone to mass wasting. mapped as Qakp2 were indeed present at the time of the first aerial photography of the region in 1

Qal Kp W W 8 Qal 5 1938, but General Land Office (GLO) maps from the 1890s do not show the course of the Keya eastern Great Plains. The northern half and southern one-quarter of the Naper Quadrangle lie 0 1 5 4 80 Kp 0 1 1 1 Qp1 1 8 1 R R within the United States Department of Agriculture Natural Resources Conservation Service 9 Paha in sufficient detail to allow an early historic qualification of the age of these deposits. 0 8 Alluvial sands on high terraces (Pleistocene) 0 0 Qas 1 0 0 8 0 0 Qapc2 Qf 0 W Broadwater Formation (Neogene; Pliocene) These deposits may be as young as early historic, but additional age control is available. Areas (NRCS) Major Land Resource Area (MLRA) 66 Dakota-Nebraska Eroded Tableland, whereas Nov 1 Nb 8 0 19 20 21 22 23 24 19 0 mapped as Qakp2 consist of silty surface strata underlain by sands and they may be flooded at Very pale brown, well- to moderately sorted, very fine to fine sands containing granules and the slopes along the valleys of the Keya Paha and Niobrara rivers are included in MLRA 63B 000m 20 1 47 50 9 47 60 N 5 60 Southern Rolling Pierre Shale Plains (United States Department of Agriculture, Natural 0 White and light brown, medium to very coarse sands and pebbly to cobbly sands, as well as high flow stages of the Keya Paha River. Mapping units Qakp2 and Qakp3 (below) include a pebbles. 0 5 8 a few, very low terraces. Resources Conservation Service, 2006). 1 1 c 1 9 1 n gravels. 0 8 Po 8 0 5 5 0 Qapc2 0 2 Qapc4 Kp In the Naper Quadrangle, deposits mapped as Qas contain few to common granules to pebbles of 0

0 0 Qp1 17 The topography of the Naper Quadrangle is varied and the landscape is scenic. The total relief 50 This unit is mapped in the uplands near the western edge of the quadrangle, where it overlies Qakp3 Quaternary alluvium of the Keya Paha River (Holocene) crystalline rock types (e.g., granitic rocks and vein quartz), as well as clasts of opaline and carbonate-cemented sandstones eroded from the Ogallala Group. Multiple clasts of Ogallala on the land surface within Nebraska portion of the Marty Quadrangle is greater than 450 ft (137 1800 strata of the Ogallala Group. Diffendal et al. (2008) mapped the Broadwater Formation at a very coarse scale of resolution in this part of Boyd County. Very pale brown, pale brown, brownish gray, and grayish brown, well -sorted very fine sand and Group sandstone, with what appear to be spherulitic carbonate cements, were found in a roadcut m), from the lowest elevation in the Valley to the flat summits of hills at the 19 western margin of the map in section 31 of T. 35 N., R. 15 W. and section 6 of T. 34 N., R. 15 00 silty very fine sand. between sections 20 and 21 of T. 34 N., R. 15 W., at the edge of the ancient alluvial terrace

0 5 C Qapc4 W. Topographic subdivisions within the Naper Quadrangle are as follows: 0 1 0 re between the Keya Paha and Niobrara rivers. 2 9 Nov 5 e Fort Randall Formation of the Ogallala Group (Neogene, Middle Miocene) Nb 0 8 k Nofr 0 1 4759 Qal 4759 Areas mapped as Qakp3 are distal floodplain deposits that appear smooth -surfaced in aerial Kp Kp photography dating back to 1938. Alluvial deposits in these areas must be older than those in the Qes1 Eolian sands locally reworked from alluvial terrace sands (Quaternary) 1. The valleys of the Keya Paha and Niobrara rivers (Fig. 1) in the southern half of the map, 20 1 Massive, laminated, and rippled light gray, yellow, pale yellow, and light yellowish brown 5 0 9 18 1 0 5 5 5 8 as well as that of Ponca Creek in the northwestern quarter of the map. The northern 9 0 0 0 more proximal mapping units Qakp1 and Qakp2. Areas mapped as Qakp3 consist of silty 30 1 25 0 weakly-consolidated siltstones, which locally contain nodules of authigenic carbonate; also 29 27 Qp1 valley wall of the Keya Paha River, which is eroded into the Pierre Shale, is steep and 28 26 30 includes beds of light yellowish brown and pale brown well-sorted very fine to fine sands and surface strata underlain by sands and it is likely that they a re very rarely, if ever, flooded. White to very pale brown fine sand. 1 2 9 0 0 5 heavily dissected; it exhibits more than 300 ft (91 m) of relief. Pierre Shale is also 0 Nov 0 lenses of pebble to cobble gravels. Mapping units Qakp2 and Qakp3 include a few, very low terraces. 50 ezposed on the lower slopes of the valley walls of Ponca Creek. 19 This unit is mapped in the southern third of the quadrangle atop the ancient fluvial terrace

1 This unit is lithologically distinct from the upper part of the Ogallala Group in the area, and we Quaternary alluvium of smaller streams (Holocene to modern) between the Keya Paha and Niobrara rivers. It is interpreted as wind-reworked alluvial terrace Qal 1 9 1 Qal 9 9 5 0 0 2. The dissected flats atop the divide between Ponca Creek and the Keya Paha River, in the 0 1 Qp1 0 0 7 50 have mapped it as the Fort Randall Formation on the basis of a comparison with Skinner and sediment. Qp2 middle of the map area. These flats slope gently southeastward and they are underlain by W Nov Qp1 Taylor (1967), who described the type section of that unit in the Bijou Hills in northeastern Clayey silt, silt, sandy silt, and sand. Nov 4758 4758 Charles Mix County, South Dakota. Our mapping of the Fort Randall Formation can be Qes2 Eolian sands locally reworked from alluvial terrace sands, with a surficial silty component Late Pleistocene loess and the Miocene sediments of the Ogallala Formation, and they considered provisional pending a complete re-examination of Neogene stratigraphy in the Small, low-order streams in the mapped area deposit clayey silt, silt, sandy silt, and fine to (Quaternary) have several, small, ovoid deflation basins that contain water during wet periods. A few, Qf 2 2 0 northwest-to-southeast-oriented erosional remnants of Ogallala Group strata rise from 0 0 5 0 0 1 0 0 0 8 enclosing region of Nebraska. Fossils from the Fort Randall Formation in its type area place it medium sand. Streams draining basins dominated by surficial materials of either Peoria Loess or 0 85 50 2 2 1 these flats, the highest and most prominent being the Twin Buttes (Fig. 2) in the southern 0 0 within the span of the Barstovian North American Land Mammal Age (16.3- 13.6 Ma). Pierre Shale should be expected to deposit more silt and clay than do other streams. Streams White to very pale brown fine sand and silty fine sand. 0 2 Kp 00 half of section 12 of T. 34 N., R. 15 W. 0 1 9 draining the Pierre Shale may include deposits dominated by coarse sand- to pebble-sized clasts 5 0 1 9 0 5 5 0 0 1 This unit is mapped in the southern third of the quadrangle atop the ancient fluvial terrace 2 9 Sands and gravels are present near or at the base of this unit, and these sediments may produce of shale. 0 0 small quantities of groundwater. between the Keya Paha and Niobrara rivers. It is interpreted as wind-reworked alluvial terrace 3. The dissected uplands eroded from Pliocene sands and gravels on the divide between Nov 1 Qp1 9 Ponca Creek and the Keya Paha River in sections 19, 20, 29, 30, 31, and 32 of T. 35 N., 5

32 34 35 0 36 sediment, but it is also mixed with a small increment of silt that may be of either eolian or 33 Nov 31 Qan1 Modern alluvium of the Niobrara River 31 alluvial origin. R. 15 W. and in sections 5 and 6 of T. 34 N., R. 15 W. This subdivision consists of 47 1 4757 57 8 Nov Valentine Formation of the Ogallala Group (Neogene, Middle to Late Miocene) 5 gentle to steep hills with prominently flat summits. Qp2 0 Pale brown and light brownish gray silty sand and fine to coarse sand. Nb Naper 1 2 9 Quaternary alluvial fan sediments (Holocene-modern) 0 1 0 Qf 0 Dominantly unconsolidated, well-sorted, white, light brown, and pale yellow, fine to medium

5 9 5 4. The eroded ancient fluvial terrace between the Keya Paha and Niobrara rivers in the 0 0 sands with a distinct “salt and pepper” aspect due to the presence of dark mineral grains, in This mapping unit includes recently abandoned channels and accreted bars of the Miobrara 19 southern half of the map. This feature is covered with sands, of both alluvial and eolian 210 5 0 0 River. Clay, silt, sand, and gravel, composition depending on source materials. some places containing a few granules and pebbles; also contains thin layers of greenish gray origins, and it is underlain by the Pierre Shale.

T. 35 N. T. 35 N. (weathering to white), indurated opaline sandstones and white, friable, carbonate-cemented Young Quaternary alluvium of the Niobrara River (historic) A few, small, low-relief alluvial fans appear on valley-side slopes and, in one case, on the (!12 sandstones. Qan2 Bedrock and Regolith Geology 57'30" Ó Ó 57'30" dissected uplands at the western margin of the map (around the shared corners of sections 29, 30, 1 T. 34 N. T. 34 N. 9 1900 5 0 00 Most of the detailed stratigraphic work identifying the Valentine Formation and differentiating it Pale brown and light brownish gray silty sand and fine to coarse sand. 31, and 32 of T. 35 N., R. 15 W.). 20 47 The reader is referred to Joeckel et. al. (2013) for a discussion of this subject on a regional basis. 4756 0 56 195 Nov (!12 from the overlying Ash Hollow Formation was carried out farther west in the Niobrara Valley 1 9 Nov 5 (Skinner and Johnson, 1984), and little, if any, attempt has yet been made to differentiate Mapping unit Qan2 includes areas along the Niobrara River where bars have been stabilized by Peoria Loess (Late Pleistocene [Late Wisconsinan]), typically atop and amalgamated with 2050 0 Qp1 Groundwater Resources 18 1 5 Qp2 95 0 formations within the Ogallala Group in north-central Nebraska. Herein, however, we, assign vegetation and accreted since initial Euramerican settlement. These areas may be subject to shallow sandy sediments of the Ogallala Group. 0 Nofr 1 9 flooding during high-stage flow periods of the Niobrara River. Mapping unit Qan3 is likely to be 4 the unconsolidated sands of the Ogallala Group, which are widespread on the dissected flats atop Qp1 0 Potential and realized sources of groundwater in the Naper Quadrangle are the very deep, 5 4 3 2 1 underlain by Holocene alluvium. 6 6 the divide between Ponca Creek and the Keya Paha River, to the Valentine Formation of the Light brownish gray, brown, pale brown, and light yellowish brown silt and sandy silt. confined bedrock aquifers of: (1) sandstones in the mid-Cretaceous Dakota Formation, (2) the Ogallala Group. Vertebrate paleontologists have recovered diagnostic vertebrate fossils in the 1 9 Late Cretaceous Codell Sandstone Member (one or more sandstones) in upper part of the Carlile 0 0 area of Boyd County for more than 150 years. In 1857, F.V. Hayden, geologist on the Warren This mapping unit represents a thin increment of loess is mapped, as a general rule, over coarser 2 Qan3 Older Quaternary alluvium of the Niobrara River (Late Holocene) 1 Shale, (3) the Ogallala Group, and (4) alluvial aquifers in the valleys of Ponca Creek and the 0 0 1 1 Nb 1 9 9 950 0 Military Expedition, collected specimens in this area which were described by Joseph Leidy, but and more permeable sediments of the Ogallala Group on the uplands; this increment of loess 2 9 0 0 1 85 0 0 1 Keya Paha and Niobrara rivers. Sand and gravel aquifers in the Ogallala Group in this area are 5 5 0 47 0 0 47 55 1 55 many of these bones lacked adequate geographic or stratigraphic data. The University of Pale brown and light brownish gray silty sand and fine to coarse sand. may be partially amalgamated with the uppermost unconsolidated sediments of the Ogallala 8 5 strongly limited in thickness and yield, and in contrast to those in Cretaceous strata, are also very 1950 0 1900 Nebraska State Museum (UNSM) worked a site near the Twin Buttes (“Forked Hills”; Fig. 2), Group, making it difficult to discern as a separate stratigraphic unit. shallow and unconfined. Likewise, the alluvial aquifers are shallow and unconfined. 1 9 0 0 and replicated many of Hayden’s taxa suggesting this spot was the source of the material he Areas mapped as Qan3 are parts of the floodplain of the Niobrara River, but they are likely to described in the 1850s. In total, there are nine UNSM fossil vertebrate localities from Boyd have been stable since the mid-19th century, if not earlier. These areas may still be flooded from 2 Peoria Loess (Late Pleistocene [Late Wisconsinan]) atop and amalgamated with shallow 05 Qp2 References 0 1 9 0 County. All of these sites contain Miocene-age taxa characteristic of the Barstovian (Ba2) North time to time and may have received comparatively small increments of overbank sediment since sands and gravels of the Broadwater Formation. 0 2 1 0 00 9 5 0 5 9 1 1 9 American Land Mammal Age including Untermannerix, Megasminthus, Mylagaulus, Eucastor the first Euramerican settlement of the area. Mapping unit Qan3 is likely to be underlain by 19 0 5 0 Diffendal, R.F., Jr., Voorhies, M.R., Voorhies, E.J., LaGarry, H.E., Timperley, C.L., and 0 0 tortus, Aelurodon ferox, Cynarctus saxatilis, Pliohippus mirabilis, Ustatochoerus medius, older Holocene and Late Pleistocene alluvium. Light brownish gray, brown, pale brown, and light yellowish brown silt and sandy silt. 0 Nov Perkins, M.E., 2008, Geologic map of the O’Neill 1 x 2 Quadrangle, Nebraska, with 190 20 Longirostromeryx, and Procranioceras (Tedford et al., 2004). In the least, this age assignment 00 configuration maps of surfaces of formations. School of Natural Resources, Conservation 850 strongly suggest that strata of the Ogallala Group in the area are not equivalent to the Ash 1 Qapc1 Youngest Quaternary alluvium of Ponca Creek (modern) This mapping unit represents a thin increment of loess is mapped over much coarser and more and Survey, Institute of Agriculture and natural Resources, University of Nebraska-Lincoln, 4754 4754 12 7 Hollow Formation. permeable sands and gravels of the Broadwater Formation. 9 11 Geologic Map GMC-34. 1 8 1 10 1 7 9 9 00 T 9 Very pale brown and light brownish gray medium to very coarse sand with pebble gravels 0 1 9 w 3 Joeckel, R.M., Johnson, D., Howard, L.M., and Kuzila, M.S., 2013, Surficial Geology of the

0 5 0 in 0 Large masses and blocks of greenish gray opaline sandstones, which are considered diagnostic of 1 Qp1 containing common clasts of Pierre Shale ironstone or carbonate nodules and of Ogallala 9 19 F Fill Gross 7.5 Minute Quadrangle, Nebraska Portion (STATEMAP). Conservation and Survey 5 5 0 0 the Ogallala Group (e.g., Skinner and Taylor, 1967), can be found within or atop these sands in 1 1 Group sandstone. 9 Qp1 9 Division, School of Natural Resources, Institute of Agriculture and Natural Resources, 5 B 50 0 u t multiple areas, but particularly on flat hill summits (e.g., along the line between the NE¼ of Artificial fill derived from local sources. 1 t University of Nebraska – Lincoln, Lincoln, Nebraska 9 e 5 s 0 section 36, T. 35 N., R. 15 W. and the NW¼ of section 31, T. 35 N., R. 14 W.; and on the This mapping unit differentiates the modern, entrenched channel belt and bars of Ponca Creek, 1850 [http://snr.unl.edu/data/geologysoils/digitalgeologicmaps/digitalgeologicmaps.asp].

0 5 crescent-shaped summit near the shared corner of sections 27, 28, 33, and 34, T. 35 N., R. 15 which is a small, low sinuosity (S < 1.2) stream in the map area. Ponca Creek is entrenched into This mapping unit is intended to portray significant accumulations of artificial fill in dams, road 8 Skinner, M.F., and Johnson, F.W., 1984, Tertiary stratigraphy and the Frick Collection of fossil 1 1 9 1950 0 W.). Nonetheless, there is no landform on the quadrangle that is distinctly capped by a single, 0 its own alluvium (Qapc2 and Qapc4) within the mapped area. Matu re bur oaks (Quercus embankments, and other manmade structures. vertebrates from north-central Nebraska. Bulletin of the American Museum of Natural 1 8 1 47 thick, and continuous layer of opaline sandstone. 4753 5 8 53 macrocarpa) and other trees along the banks of the entrenched stream indicate that it has been in 0 5 History 178, article 3. 0 1 85 that state for several decades at minimum. The current channel of Ponca Creek in this area is, Skinner, M.F., and Taylor, B.E., 1967, A revision of the geology and paleontology of the Bijou 0 1 12 W Water 9 (! 1 0 The Twin Buttes (S½ of section 12, T. 34 N., R. 15 W.; Fig. 2) are capped with a white, friable, 1 8 0 195 along much of its length, a single-thread planform with alternate bars. Gentle bends in this 1 8 5 0 Hills, South Dakota. American Museum Novitates 2300:1-53. Kp 8 0 0 0 0 1 0 carbonate-cemented, medium sandstone. This sandstone exhibits trough cross strata 25 to 40 cm 1 1 8 planform have wavelengths of 100-150 m. There are, however, slightly braided stretches and a 8 8 0 Tedford, R.H., Albright, L.B., III, Barnosky, A.D., Ferrusquia-Villafranca, I., Hunt, R.M., Jr., 1 1 0 0 0 7 8 0 0 1 Qp1 Landslide 5 5 1 8 in thickness that record northeasterly paleoflow, and it also contains common rhizoliths and 0 9 0 1 0 0 9 few, larger meanders with point bars. Immediately downstream from the mapped area, Ponca 0 0 00 Storer, J.E., Swisher, C.C., III, Voorhies, M.R., Webb, S.D., Whistler, D.P., 2004, 1 800 invertebrate burrows. Creek is significantly more sinuous and it currently exhibits much larger meanders. The Geologic contact – approximately located Mammalian biochronology of the Arikareean through Hemphillian interval (Late Oligocene 1 sediments of mapping unit Qapc1 appear to be inset into those of a larger, predecessor Ponca

0 8 17 5 1 through Early Pliocene Epochs). In: Woodburne, M.O. (Ed.), Late Cretaceous and Cenozoic 5 16 0 7 7 18 5 15 14 13 18 1 0 Sediments at the surface of this mapping unit may have been reworked by strong winds during Creek, which had large meanders with wavelengths of approximately 1.2 km. 1 0 Mammals of North America, Geochronology and Biostratigraphy: Columbia University 7 1 0 5 Prominent high-relief oriented ridge line interpreted as a product of eolian erosion 0 1 8 7 5 the Pleistocene, but we interpret the upper surface of the Ogallala Group in the mapped area as 7 1 0 175 5 18 Press, New York, pp. 167-231. 0 0 5 47 4752 0 52 being primarily an erosional surface. Qapc2 Young Quaternary alluvium of Ponca Creek (Holocene) 18 00 1 United States Department of Agriculture, Natural Resources Conservation Service, 2006, Land 8 Low-relief oriented feature mapped from aerial photography and interpreted as a product 0 17 0 0 0 1 1 18 9 Resource Regions and Major Land Resource Areas of the United States, the Caribbean, and K 7 00 00 0 of eolian processes 1 Gray, light brownish gray, very pale brown, and brown sandy silt, silty fine sand and fine to 5 17 0 EY 0 7 Qakp1 Very young Quaternary alluvium of the Keya Paha River (post- ca. 1950) Qakp2 5 A 1 the Pacific Basin. U.S. Department of Agriculture Handbook 296. 0 7 coarse sand. 5 0 55' Ó Ó 55' ! Historic CSD test hole (mud rotary boring) 1 7 0 Very pale brown to pale brown, well-sorted very fine sand. 0 1 1 8 The areas mapped as Qapc2 are partially wooded and show weak evidence for lateral accretion 0 7 0 0 0 0 17 0 !. 17 in relict point bars and they also exhibit a few flood channels. We speculate that these deposits Test hole cored in 2013 mapping season 50 These deposits result from the migration of meander bends in the Keya Paha River since ca. 1

8 0 Qakp3 represent a higher-discharge regime of Ponca Creek in the past. Since the entrenchment of 0 R Kp 1 1950. Individual bends have migrated laterally and downstream some 50 to 100 at some points E 7 1 00 IV 7 17 5 Simplified Lithologic Logs of New Test Holes Drilled in this Study R Qakp2 0 5 Ponca Creek, these deposits are now part of one or more alluvial terraces. 0 47 during the past six decades, although other stretches have migrated very little, if at all . The 47 1 51 51 8 170 5 0 0 sediments being transported by the modern Keya Paha River are distinctly fine r than those being 0 0 7 17 1 carried by Ponca Creek, a smaller stream. 50 AHA 0 Qas P 170 1700 19 1800 22 800 Qakp3 19 1700 1700 1 23 0 21 0 24 8 20 0 1 1 70 6 Kp 1 5 1 0

8 8 1850 Qes2 0 0 75 Qakp2 1750 1 1 1750 8 0 0 1 8 800 0 1700 47 1 0 47 50 0 50 2 1 8 75 1 0 0 1 80 87 1 1 0 8 5 0

1 70 0 0 85 0 1 1 6 8 18 0 Qes2 0 1880

1

8

4

0 1 820 1800 47 4749 1750 49 28 26 Figure 1. View south to southwest from the summit of east Twin Butte in SE¼ of section 12, T. 34 N., R. 15 W. (see Fig. 2), looking acr oss flats on lower Figure 2. Twin Buttes, photographed from south (east is to right). These features are eroded from Ogallala Group strata, int erpreted herein as Valentine 29 30 30 27 25 0 Ogallala Group sediments and into valleys of Keya Paha and Niobrara rivers, which are eroded into Pierre Shale. Formation, and are capped by friable, trough cross-stratified sandstone. 170 1890

O C 0 Kp D 0 80 Y O 5 1 O C 8 B 1 LT 0 O 182 R H 0 E 7 V 18 Qes1 R I Qan2 1 6 Alluvial sediments Eolian sed. 5 Slope sediments Qf 0 Qan1 Q u 47 0 47 48 5 48 7 a 1 Qal Qakp1 Qakp2 Qakp3 Qan1 Qan2 Qan3 Qapc1 Qapc2 Qapc4 Qf

0 t A 0 R 17 e A Qes1 Qes2 Qp1 Qp2 r R n 0 a 1880 80 0 B 1 0 r 7 O 1830 1 I y N Kp Qas

00 18 Qes2 1 7 35 0 5 0 32 Qes2 33 5 0 0 7 36 8 34 1 Qan1 31 1 Continental sediments 31 Qas CO OYD 1 B O 0 Qes2 Qan1 6 C 0 and sed. rocks 0 6 LT 8 85 0 HO 1 1 P

42°52'30" 42°52'30" l 000m i 99°07'30" 490 491 492 493 5' 494 495 496 2'30" 497 R. 15 W. R. 14 W. 499 E 99°00' o c

Nb e n N e e

SCALE 1:24,000 o g M 1 0.5 0 1 e n i Miles SAINT e HERRICK BONESTEEL o CHARLES Nov c

1,000 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 e Feet n Nofr e 1 0.5 0 1 Kilometers NAPER BUTTE NAPER Marine sedimentary rocks U NW NW .

Projection: Universal Transverse Mercator, zone 14 North, NAD83. CONTOUR INTERVAL 10 FEET C This geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program. The

1000-meter Universal Transverse Mercator grid ticks shown in blue. r views and conclusions contained in this document are those of the authors and should not be interpreted as DATUM IS MEAN SEA LEVEL NEBRASKA e Kp t necessarily representing the official policies, either expressed or implied, of the U.S. Government. a

Contours from the Nebraska Department of Natural Resources, c Magnetic North NAPER BUTTE e Compiled from USGS 7.5 minute topographic quadrangles. Declination DUSTIN o o SW SW u Approximately 5.11 MAP LOCATION s 2013 Additional base data derived from the 2010 TIGER line files. Ø$