[{"legend_id":77297,"source_id":133,"scale":"medium","map_unit_name":"Alluvium","strat_name":null,"age":"Quaternary","lith":"Major:{coarse alluvium,fine alluvium}","descrip":"Clay to boulder-size clasts with locally abundant organic material. Thickness up to 75 ft (23m).","comments":"Original map source: Martin, J.E., Sawyer, J.F., Fahrenbach, M.D., Tomhave, D.W., and Schulz, L.D.,  2004, Geologic Map of South Dakota: South Dakota Geological  Survey, GM 10, scale 1:500,000.","t_age":0.0,"b_age":2.588,"b_interval":421,"t_interval":421,"strat_name_id":null,"unit_id":null,"lith_classes":["sedimentary"],"lith_types":["siliciclastic"],"lith_id":[154],"color":"#d6e165","area":8124.779,"tiny_area":null,"small_area":null,"medium_area":8124.779,"large_area":7368.885},{"legend_id":77426,"source_id":133,"scale":"medium","map_unit_name":"Arikaree Group","strat_name":"Rosebud Formation; Harrison Formation; Turtle Butte Formation; Monroe Creek Formation; Sharps Formation","age":"Oligocene - Miocene","lith":"Major:{siltstone,sandstone}, Minor:{claystone,felsic volcanic,marlstone}","descrip":"Includes: Rosebud Formation (Miocene)- Pink siltstone with channel sandstone and concretions. Thickness up to 250 ft (76 m). Harrison Formation (Miocene)- Gray, silty sandstone and reworked volcanic ash with calcareous siltstone and marl. Thickness 180 ft (55 m).  Turtle Butte Formation (Miocene)- Light-green to gray siltstone with sandstone channels containing claystone pebbles. Thickness 65 ft (20 m).  Monroe Creek Formation (Oligocene)- Tan to grayish-tan, massive sandy siltstone and reworked volcanic ash. Thickness 100 ft (30 m).  Sharps Formation (Oligocene)- Pink siltstone and claystone with concretionary layers, paleochannels, and beds of reworked volcanic ash. Thickness 360 ft (110 m).","comments":"Original map source: Martin, J.E., Sawyer, J.F., Fahrenbach, M.D., Tomhave, D.W., and Schulz, L.D.,  2004, Geologic Map of South Dakota: South Dakota Geological  Survey, GM 10, scale 1:500,000.","t_age":17.0875,"b_age":23.875,"b_interval":21,"t_interval":13,"strat_name_id":[843,3196,73311,73312,73456,73457,79875,79876],"unit_id":[3140,3141,9780,9864],"lith_classes":["igneous","sedimentary"],"lith_types":["siliciclastic","volcanic"],"lith_id":[6,9,10,63],"color":"#F4B470","area":6124.333,"tiny_area":null,"small_area":null,"medium_area":6124.333,"large_area":6124.333},{"legend_id":78067,"source_id":133,"scale":"medium","map_unit_name":"Carlile Shale","strat_name":"Carlile Shale","age":"Late Cretaceous","lith":"Major:{shale}, Minor:{carbonate,sandstone,marlstone}","descrip":"Dark-gray to black, silty to sandy shale with several zones of septarian, fossiliferous, carbonate concretions. Contains up to three sandstone units in the upper portion of the formation and sandy calcareous marl at the base.  Thickness up to 330 ft (100 m).","comments":"Original map source: Tomhave, D.W., and Schulz, L.D., 2004, Bedrock Geologic Map Showing Configuration of the Bedrock Surface in South Dakota East of the Missouri River, South Dakota Geological  Survey, GM 9, scale 1:500,000.","t_age":89.8,"b_age":92.875,"b_interval":34,"t_interval":34,"strat_name_id":[316,7420,7836],"unit_id":[2938,3206,5885,5892,6031],"lith_classes":["sedimentary"],"lith_types":["carbonate","siliciclastic"],"lith_id":[8,10,18],"color":"#7ee000","area":8013.541,"tiny_area":null,"small_area":null,"medium_area":8011.985,"large_area":8011.985},{"legend_id":78377,"source_id":133,"scale":"medium","map_unit_name":"Colluvium","strat_name":null,"age":"Quaternary","lith":"Major:{coarse alluvium,fine alluvium}","descrip":"Clay to boulder-size clasts forming rubble residuum and talus. Thickness up to 30 ft (9m).","comments":"Original map source: Martin, J.E., Sawyer, J.F., Fahrenbach, M.D., Tomhave, D.W., and Schulz, L.D.,  2004, Geologic Map of South Dakota: South Dakota Geological  Survey, GM 10, scale 1:500,000.","t_age":0.0,"b_age":2.588,"b_interval":421,"t_interval":421,"strat_name_id":null,"unit_id":null,"lith_classes":["sedimentary"],"lith_types":["siliciclastic"],"lith_id":[154],"color":"#d6e165","area":35.525,"tiny_area":null,"small_area":null,"medium_area":35.525,"large_area":24.041},{"legend_id":78614,"source_id":133,"scale":"medium","map_unit_name":"Dam","strat_name":null,"age":null,"lith":"","descrip":null,"comments":"Original map source: Martin, J.E., Sawyer, J.F., Fahrenbach, M.D., Tomhave, D.W., and Schulz, L.D.,  2004, Geologic Map of South Dakota: South Dakota Geological  Survey, GM 10, scale 1:500,000.","t_age":null,"b_age":null,"b_interval":null,"t_interval":null,"strat_name_id":null,"unit_id":null,"lith_classes":null,"lith_types":null,"lith_id":null,"color":null,"area":2.411,"tiny_area":null,"small_area":null,"medium_area":2.411,"large_area":2.411},{"legend_id":78987,"source_id":133,"scale":"medium","map_unit_name":"Eolian Deposits","strat_name":null,"age":"Quaternary","lith":"Major:{silt,sand}","descrip":"(loess and sand dune) Silt to medium-grained sand. Deposited as sand sheets and barchan, linear, and dome-like dunes and as veneer on uplands. Thickness up to 300 ft (91m).","comments":"Original map source: Martin, J.E., Sawyer, J.F., Fahrenbach, M.D., Tomhave, D.W., and Schulz, L.D.,  2004, Geologic Map of South Dakota: South Dakota Geological  Survey, GM 10, scale 1:500,000.","t_age":0.0,"b_age":2.588,"b_interval":421,"t_interval":421,"strat_name_id":null,"unit_id":null,"lith_classes":["sedimentary"],"lith_types":["siliciclastic"],"lith_id":[3,4],"color":"#ffff96","area":7095.28,"tiny_area":null,"small_area":null,"medium_area":7095.28,"large_area":7042.208},{"legend_id":81304,"source_id":133,"scale":"medium","map_unit_name":"Niobrara Formation","strat_name":"Niobrara Formation","age":"Late Cretaceous","lith":"Major:{chalk,marlstone,shale}, Minor:{bentonite,sand}","descrip":"White to dark-gray argillaceous chalk, marl, and shale.  Weathers yellow to orange. Contains thin, laterally continuous bentonite beds, chalky carbonaceous shale, minor sand, and small concretions. Thickness up to 150 ft (46 m).","comments":"Original map source: Martin, J.E., Sawyer, J.F., Fahrenbach, M.D., Tomhave, D.W., and Schulz, L.D.,  2004, Geologic Map of South Dakota: South Dakota Geological  Survey, GM 10, scale 1:500,000.","t_age":83.6,"b_age":89.8,"b_interval":34,"t_interval":34,"strat_name_id":[1425,72437],"unit_id":[5872,5884,9854,9899,15899],"lith_classes":["sedimentary"],"lith_types":["carbonate","siliciclastic"],"lith_id":[3,8,92],"color":"#72e200","area":495.276,"tiny_area":null,"small_area":null,"medium_area":495.276,"large_area":332.8},{"legend_id":81305,"source_id":133,"scale":"medium","map_unit_name":"Niobrara Formation","strat_name":"Niobrara Formation","age":"Late Cretaceous","lith":"Major:{chalk,marlstone,shale}, Minor:{bentonite,sand}","descrip":"White to dark-gray argillaceous chalk, marl, and shale.  Weathers yellow to orange. Contains thin, laterally continuous bentonite beds, chalky carbonaceous shale, minor sand, and small concretions. Thickness up to 150 ft (46 m).","comments":"Original map source: Tomhave, D.W., and Schulz, L.D., 2004, Bedrock Geologic Map Showing Configuration of the Bedrock Surface in South Dakota East of the Missouri River, South Dakota Geological  Survey, GM 9, scale 1:500,000.","t_age":83.6,"b_age":89.8,"b_interval":34,"t_interval":34,"strat_name_id":[1425,72437],"unit_id":[3205,5884,5891],"lith_classes":["sedimentary"],"lith_types":["carbonate","siliciclastic"],"lith_id":[3,8,92],"color":"#72e200","area":12134.41,"tiny_area":null,"small_area":null,"medium_area":12134.41,"large_area":12134.41},{"legend_id":81390,"source_id":133,"scale":"medium","map_unit_name":"Ogallala Group","strat_name":"Ash Hollow Formation; Valentine Formation; Fort Randall Formation","age":"Miocene - Pliocene","lith":"Major:{sandstone,limestone,siltstone}, Minor:{claystone}, Incidental:{bentonite, conglomerate}","descrip":"Includes: Ash Hollow Formation- White, tan, and gray, well-cemented, calcareous sandstone and silty limestone often referred to as \"mortar beds\". Thickness 90-250 ft 27-76 m) Valentine Formation- Gray, unconsolidated, fine- to coarse grained, fluvial siltstone, channel sandstone, and gravel derived from western sources. Thickness 175-225 ft (53-69 m). Fort Randall Formation- Pink and gray claystone with interbedded sandstone. Also includes green to gray orthoquartzite, bentonitic clay, and conglomerate. Thickness up to 130 ft (40 m).","comments":"Also includes the Thin Elk, Bon Homme, Herrick, Medicine Root, and \"western derived\" gravels. Original map source: Martin, J.E., Sawyer, J.F., Fahrenbach, M.D., Tomhave, D.W., and Schulz, L.D.,  2004, Geologic Map of South Dakota: South Dakota Geological  Survey, GM 10, scale 1:500,000.","t_age":6.7678,"b_age":13.27,"b_interval":13,"t_interval":10,"strat_name_id":[71,2187,78927],"unit_id":[3134,3135,3186,3187],"lith_classes":["sedimentary"],"lith_types":["carbonate","siliciclastic"],"lith_id":[6,9,10,14,30],"color":"#FFFF00","area":3515.998,"tiny_area":null,"small_area":null,"medium_area":3515.998,"large_area":3515.998},{"legend_id":81611,"source_id":133,"scale":"medium","map_unit_name":"Outwash, Terrace","strat_name":null,"age":"Pleistocene","lith":"Major:{clay,sand,gravel}","descrip":"Heterogeneous clay to gravel of glaciofluvial orgin. Thickness up to 60 ft (18m)","comments":"Original map source: Martin, J.E., Sawyer, J.F., Fahrenbach, M.D., Tomhave, D.W., and Schulz, L.D.,  2004, Geologic Map of South Dakota: South Dakota Geological  Survey, GM 10, scale 1:500,000.","t_age":0.0117,"b_age":2.588,"b_interval":4,"t_interval":4,"strat_name_id":null,"unit_id":null,"lith_classes":["sedimentary"],"lith_types":["siliciclastic"],"lith_id":[2,3,93],"color":"#e8e29d","area":53.296,"tiny_area":null,"small_area":null,"medium_area":53.296,"large_area":53.296},{"legend_id":81844,"source_id":133,"scale":"medium","map_unit_name":"Pierre Shale","strat_name":"Pierre Shale","age":"Late Cretaceous","lith":"Major:{shale,bentonite}, Minor:{sandstone,conglomerate,carbonate}","descrip":"Blue-gray to dark-gray, fissile to blocky shale with persistent beds of bentonite, black organic shale, and light-brown chalky shale. Contains minor sandstone, conglomerate, and abundant carbonate and ferruginous concretions. Thickness up to 1,000 ft (305 m).","comments":"Original map source: Martin, J.E., Sawyer, J.F., Fahrenbach, M.D., Tomhave, D.W., and Schulz, L.D.,  2004, Geologic Map of South Dakota: South Dakota Geological  Survey, GM 10, scale 1:500,000.","t_age":66.0,"b_age":84.05,"b_interval":34,"t_interval":34,"strat_name_id":[4191,72548],"unit_id":[5871,5883,15898],"lith_classes":["sedimentary"],"lith_types":["carbonate","siliciclastic"],"lith_id":[8,10,14,18],"color":"#72e200","area":33043.62,"tiny_area":null,"small_area":null,"medium_area":33043.62,"large_area":32119.951},{"legend_id":81845,"source_id":133,"scale":"medium","map_unit_name":"Pierre Shale","strat_name":"Pierre Shale","age":"Late Cretaceous","lith":"Major:{shale,bentonite}, Minor:{sandstone,conglomerate,carbonate}","descrip":"Blue-gray to dark-gray, fissile to blocky shale with persistent beds of bentonite, black organic shale, and light-brown chalky shale. Contains minor sandstone, conglomerate, and abundant carbonate and ferruginous concretions. Thickness up to 1,000 ft (305 m).","comments":"Original map source: Tomhave, D.W., and Schulz, L.D., 2004, Bedrock Geologic Map Showing Configuration of the Bedrock Surface in South Dakota East of the Missouri River, South Dakota Geological  Survey, GM 9, scale 1:500,000.","t_age":66.0,"b_age":83.6,"b_interval":34,"t_interval":34,"strat_name_id":[4191,72548],"unit_id":[5883,5890],"lith_classes":["sedimentary"],"lith_types":["carbonate","siliciclastic"],"lith_id":[8,10,14,18],"color":"#72e200","area":63295.124,"tiny_area":null,"small_area":null,"medium_area":63295.124,"large_area":63295.124},{"legend_id":83078,"source_id":133,"scale":"medium","map_unit_name":"Terrace Deposits","strat_name":null,"age":"Quaternary","lith":"Major:{coarse alluvium,clay}","descrip":"Clay to boulder-size clasts deposited as pediments, paleochannels, and terrace fills of former flood plains. Thickness up to 75 ft (23m).","comments":"Original map source: Martin, J.E., Sawyer, J.F., Fahrenbach, M.D., Tomhave, D.W., and Schulz, L.D.,  2004, Geologic Map of South Dakota: South Dakota Geological  Survey, GM 10, scale 1:500,000.","t_age":0.0,"b_age":2.588,"b_interval":421,"t_interval":421,"strat_name_id":null,"unit_id":null,"lith_classes":["sedimentary"],"lith_types":["siliciclastic"],"lith_id":[93,154],"color":"#ebfd4c","area":6329.025,"tiny_area":null,"small_area":null,"medium_area":6329.025,"large_area":5790.816},{"legend_id":83122,"source_id":133,"scale":"medium","map_unit_name":"Tertiary, undifferentiated","strat_name":null,"age":"Miocene - Pliocene","lith":"Major:{fine alluvium,siltstone,conglomerate sandstone}, Minor:{coarse alluvium}","descrip":"Light greenish-brown and light yellowish-tan to orangish-brown clay, silty clay, and fine sand; light-brown to pink siltstone; green, massive, orthoquartzite conglomerate; and multicolored quartz- and feldspar-rich sand and gravel. Includes equivalents of the Ogallala Group Ash Hollow, Valentine, and Fort Randall Formations. Also includes the Thin Elk, Bon Homme, Herrick, Medicine Root, and \"western derived\" gravels. Thickness up to 70 ft (21 m).","comments":"Original map source: Tomhave, D.W., and Schulz, L.D., 2004, Bedrock Geologic Map Showing Configuration of the Bedrock Surface in South Dakota East of the Missouri River, South Dakota Geological  Survey, GM 9, scale 1:500,000.","t_age":2.588,"b_age":23.03,"b_interval":13,"t_interval":10,"strat_name_id":null,"unit_id":null,"lith_classes":["sedimentary"],"lith_types":["siliciclastic"],"lith_id":[9,10,14,154],"color":"#eeff00","area":133.868,"tiny_area":null,"small_area":null,"medium_area":133.868,"large_area":133.868},{"legend_id":83650,"source_id":133,"scale":"medium","map_unit_name":"water","strat_name":null,"age":null,"lith":"","descrip":null,"comments":"Original map source: Martin, J.E., Sawyer, J.F., Fahrenbach, M.D., Tomhave, D.W., and Schulz, L.D.,  2004, Geologic Map of South Dakota: South Dakota Geological  Survey, GM 10, scale 1:500,000.","t_age":null,"b_age":null,"b_interval":null,"t_interval":null,"strat_name_id":null,"unit_id":null,"lith_classes":null,"lith_types":null,"lith_id":null,"color":"","area":1692.05,"tiny_area":null,"small_area":null,"medium_area":1692.05,"large_area":1683.126},{"legend_id":83755,"source_id":133,"scale":"medium","map_unit_name":"White River Group","strat_name":"Brule Formation; Chadron Formation; Chamberlain Pass Formation; Slim Buttes Formation","age":"Eocene - Oligocene","lith":"Major:{claystone,siltstone,sandstone}, Minor:{mudstone,conglomerate,bentonite}","descrip":"Includes: Brule Formation (Oligocene)- White, pink, light-green, and light-brown, massive to thin-bedded, bentonitic claystone, tuffaceous siltstone, and well-bedded, calcareous, tuffaceous quartz sandstone. Thickness up to 150 ft (46 m).  Chadron Formation (Eocene)- Upper beds are gray, light-brown to maroon bentonite, claystone, siltstone tuffaceous fine-grained sandstone, and local, silicified carbonate lenses. Basal portion consists of poorly cemented, white, coarse-grained arkose and conglomerate. Thickness up to 160 ft (49 m). Chamberlain Pass Formation (Eocene)- Pale olive to pale red, mottled mudstone containing white, cross-bedded channel sandstone with basal conglomerate. Thickness up to 32 ft (10 m). Slim Buttes Formation (Eocene)- White, grayish- to yellowish-orange,pale-red to pink siltstone, clayey siltstone, bentonitic claystone,medium- to fine-grained sandstone, and conglomerate. Thickness up to 48 ft (15 m).","comments":"Original map source: Martin, J.E., Sawyer, J.F., Fahrenbach, M.D., Tomhave, D.W., and Schulz, L.D.,  2004, Geologic Map of South Dakota: South Dakota Geological  Survey, GM 10, scale 1:500,000.","t_age":24.2975,"b_age":34.875,"b_interval":24,"t_interval":21,"strat_name_id":[253,350,69319,69761,73382],"unit_id":[3144,3145,3182,3183,5869,5870,9781,9782,9861,9862],"lith_classes":["sedimentary"],"lith_types":["siliciclastic"],"lith_id":[6,7,9,10,14],"color":"#dc833b","area":5320.289,"tiny_area":null,"small_area":null,"medium_area":5320.289,"large_area":4876.928}]