Identification_Information: Citation: Citation_Information: Originator: David S. Fullerton Originator: Roger B. Colton Originator: Charles A. Bush Originator: Arthur W. Straub Publication_Date: 2004 Title: Map Showing Spatial and Temporal Relations of Mountain and Continental Glaciations on the Northern Plains, primarily in Northern Montana and Northwestern North Dakota Edition: 1.0 Geospatial_Data_Presentation_Form: map Series_Information: Series_Name: Scientific Investigations Map Issue_Identification: 2843 Publication_Information: Publication_Place: Lakewood, Colorado Publisher: U.S. Geological Survey Online_Linkage: Description: Abstract: This report is an overview of glacial limits and glacial history on the plains in northern Montana and northeastern North Dakota (long 102°-114°W.) and also in adjacent southern Alberta and Saskatchewan, Canada. In the Rocky Mountains and on the plains adjacent to the mountains in Montana, the map also depicts spatial relations of valley glaciers and piedmont ice lobes to continental ice sheets. Glacial limits east of 102°, in the United States and also in adjacent Canada, are depicted on published maps of the U.S. Geological Survey Quaternary Geologic Atlas of the United States (I-1420) map series. The limits shown here are from data compiled for the Lethbridge, Regina, Yellowstone, and Big Horn Mountains 4° x 6° quadrangles in the Quaternary Geologic Atlas series. Purpose: This geospatial database has been prepared with a degree of detail appropriate for viewing at a scale of 1:1,000,000. Because of the degree of generalization required, the map is intended for regional analysis, rather than for detailed analysis in specific areas. It depicts the geographic positions of the limits of mountain and continental glaciations and the limits of selected glacial readvances. That information provides a foundation for reconstruction of geologic history and for reconstruction of the configurations of vanished glaciers and ice sheets in the region. Supplemental_Information: The base map is simplified. Selected hydrographic features, selected towns and cities, selected physiographic features, and a grid of 1° x 2° topographic quadrangles are included to aid the reader in location of the glacial limits and other features that are depicted here on other maps at different scales. Most of the geologic data were compiled at 1:250,000 scale. The nominal reading scale of the digitized map data is 1:1,000,000. Enlargement will not restore resolution that was lost by simplification or generalization of data. Accompanying illustrations show regional directions of ice movement from Canada into the United States during maximum Illinoian glaciation, during maximum late Wisconsin glaciation, and during a later regional glacial readvance maximum. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this Federal Geographic Data Committee- compliant metadata file is intended to document the data set in nonproprietary form, as well as in ARC/INFO format, this metadata file includes some ARC/INFO-specific terminology. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2002 Currentness_Reference: Publication date Status: Progress: Complete Maintenance_and_Update_Frequency: None Planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -114.0 East_Bounding_Coordinate: -102.0 North_Bounding_Coordinate: 50.0 South_Bounding_Coordinate: 46.0 Keywords: Theme: Theme_Keyword_Thesaurus: American Geological Institute (AGI) Glossary of Geology Theme_Keyword: Alluvium Theme_Keyword: Bull Lake glaciation Theme_Keyword: Canadian Shield Theme_Keyword: Colluvium Theme_Keyword: Continental glaciation Theme_Keyword: Delta Theme_Keyword: Drumlin Theme_Keyword: Eolian deposit Theme_Keyword: Erratics train Theme_Keyword: Geologic history Theme_Keyword: Geologic map Theme_Keyword: Geology Theme_Keyword: Glacial advance Theme_Keyword: Glacial deposit Theme_Keyword: Glacial drift Theme_Keyword: Glacial erratic Theme_Keyword: Glacial history Theme_Keyword: Ice-dispersal center Theme_Keyword: Glacial limit Theme_Keyword: Glacial lake Theme_Keyword: Glacial lobe Theme_Keyword: Glacial maximum Theme_Keyword: Glacial readvance Theme_Keyword: Glaciation Theme_Keyword: Glaciofluvial deposit Theme_Keyword: Ice-molded landform Theme_Keyword: Kennedy glaciation Theme_Keyword: Lacustrine deposit Theme_Keyword: Laurentide ice sheet Theme_Keyword: Laurentide glaciation Theme_Keyword: Lava Creek B tephra Theme_Keyword: Moraine Theme_Keyword: Mountain glaciation Theme_Keyword: Nunatak Theme_Keyword: Outwash deposit Theme_Keyword: Outlet-glacier Theme_Keyword: Paleosol Theme_Keyword: Piedmont ice lobe Theme_Keyword: Pinedale glaciation Theme_Keyword: Quaternary geology Theme_Keyword: Remanent magnetic polarity Theme_Keyword: Surficial deposit Theme_Keyword: Surficial geology Theme_Keyword: Till Theme_Keyword: Valley glacier Theme_Keyword: Weathered zone Theme_Keyword: Weathering profile Place: Place_Keyword_Thesaurus: U.S. Board on Geographic Names (BGN) Place_Keyword: Bearpaw Mountains Place_Keyword: Glacier National Park Place_Keyword: Highwood Mountains Place_Keyword: Little Rocky Mountains Place_Keyword: Montana Place_Keyword: North Dakota Place_Keyword: Northern Plains Place_Keyword: Rocky Mountains Place_Keyword: Sweetgrass Hills Place_Keyword: United States Place_Keyword: Yellowstone Place: Place_Keyword_Thesaurus: Geographical Names Board of Canada Place_Keyword: Alberta Place_Keyword: Canada Place_Keyword: Cypress Hills Place_Keyword: Lethbridge Place_Keyword: Regina Place_Keyword: Saskatchewan Place_Keyword: Waterton Lakes National Park (Alberta) Temporal: Temporal_Keyword_Thesaurus: American Geological Institute (AGI) Glossary of Geology Temporal_Keyword: Bull Lake Temporal_Keyword: Early Wisconsin Temporal_Keyword: Holocene Temporal_Keyword: Illinoian Temporal_Keyword: Late Wisconsin Temporal_Keyword: Pinedale Temporal_Keyword: Pleistocene Temporal_Keyword: Pliocene Temporal_Keyword: Pre Wisconsin Temporal_Keyword: Quaternary Temporal_Keyword: Sangamon Temporal_Keyword: Tertiary Temporal_Keyword: Wisconsin Access_Constraints: None Use_Constraints: Acknowledgment of the the U.S. Geological Survey in products derived from these data will be appreciated. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Charles A. Bush Contact_Organization: U.S. Geological Survey Contact_Position: Emeritus Geophysicist Contact_Address: Address_Type: Mailing address Address: Mail Stop 980, Box 25046, Federal Center City: Lakewood State_or_Province: Colorado Postal_Code: 80225 Country: USA Contact_Voice_Telephone: (303) 236-4723 Contact_Facsimile_Telephone: (303) 236-0214 Contact_Electronic_Mail_Address: cbush@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: i-XXXX/map_screen.pdf> Browse_Graphic_File_Description: A layout of the map data and accompanying illustrations Browse_Graphic_File_Type: PDF Data_Set_Credit: The Map Showing Spatial and Temporal Relations of Mountain and Continental Glaciations on the Northern Plains, primarily in Northern Montana and Northwestern North Dakota dataset was compiled by David S. Fullerton and Roger B. Colton. It was digitized and vectorized by Charles A. Bush and Arthur W. Straub. Bush converted the data into ARC/INFO coverages and prepared the PDF version of the map. Native_Data_Set_Environment: Windows_NT, 4.0, Intel ARC/INFO version 7.2.1 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Compilation of geologic data: The accuracy of the map data is dependent on (1) the accuracy of the original source data, (2) the accuracy of transfer of that data to larger scale bases, (3) the procedures by which the compilers simplified or generalized the data, and (4) the procedures used and the objectivity exercised in integration of the data to produce the map. Consequently, aspects of accuracy for the data set cannot be quantified. Digitizing and attributing of compiled data: Data were compiled on stable-base material, digitized or scanned, vectorized, and attributed. ARC/INFO coverages were created and check plots were produced. Authors proofread check plots and reviewed digital files; made final corrections as needed; produced graphical files and imported them into graphics program to prepare cartographic product. Authors proofread cartographic product. (This map was thoroughly reviewed for conformity with U.S. Geological Survey editorial standards and stratigraphic nomenclature.) Logical_Consistency_Report: Polygon and chain-node topology are present. The ARC/INFO commands BUILD and CLEAN were run to ensure the topolgical consistency of the data set. All polygons are labeled and were tested by using the ARC/INFO command LABELERRORS. All polygons were checked for closure and intersections. Completeness_Report: These coverages contain polygons for all the map units, lines for all the glacial features, and points for all the locations of localities Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The accuracy of location of polygons, lines, and points is consistent with the map scale of 1:1,000,000. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Fullerton, D.S. Originator: Colton, R. B. Publication_Date: 1986 Title: Stratigraphy and correlation of the glacial deposits on the Montana plains in Richmond, G. M., and Fullerton, D. S., eds., Quaternary glaciations in the United States of America Geospatial_Data_Presentation_Form: paper Series_Information: Series_Name: Quaternary Science Reviews Issue_Identification: V. 5, p. 69-82 Publication_Information: Publication_Place: Amsterdam, The Netherlands Publisher: Elsevier Science Source_Scale_Denominator: 1000000 Type_of_Source_Media: mylar Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2000 Source_Currentness_Reference: Publication date Source_Citation_Abbreviation: QSR-5 Source_Contribution: Linework for the data sets Process_Step: Process_Description: Fullerton and Colton compiled geologic data from various smaller scale maps on stable-base material. Source_Used_Citation_Abbreviation: QSR-5 Process_Date: 2000 Process_Step: Process_Description: Bush and Straub vectorized linework of glacial limits and converted the data into ARC/INFO coverages using the digitizing computer program GSMCAD (by Van S. Williams, available at ) or by scanning and using "heads-up" digitizing in ARCEDIT. Process_Date: 2000 Process_Step: Process_Description: Bush acquired the Streams and Waterbodies ARC/INFO coverage at 1:2,000,000M scale from the National Atlas of the United States (). Selected streams and waterbodies were clipped out for the map area. All attributes were removed except feature type, name, and state. The Cities and Towns coverage was also acquired from the National Atlas of the United States, and selected cities clipped from the coverage to form a point coverage for the glacial map area. Process_Date: 2000 Process_Step: Process_Description: Since the National Atlas of the United States coverages do not cover the Canadian part of this map, selected streams, waterbodies, and cities were compiled (Fullerton)on stable-base material and scanned and vectorized as above and combined with the coverages created from the National Atlas of the U.S.(Bush). Process_Date: 2000 Process_Step: Process_Description: Coverages of glacial features, streams and waterbodies, and cities were plotted to allow the data to be checked and corrected or changed. Final plots were imported into graphics program to create cartographic product (Bush). Process_Date: 2001 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Point Point_and_Vector_Object_Count: 172 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: String Point_and_Vector_Object_Count: 513 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains Point_and_Vector_Object_Count: 171 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: Transverse Mercator Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.99960000 Longitude_of_Central_Meridian: -108.0 Latitude_of_Projection_Origin: 0.0 False_Easting: 0.00000 False_Northing: 0.00000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 500 Ordinate_Resolution: 500 Planar_Distance_Units: Meters Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1927 Ellipsoid_Name: Clarke 1866 Semi-major_Axis: 6378206.4 Denominator_of_Flattening_Ratio: 294.98 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: The dataset for the glacial map consists of 6 coverages. > gla_net > gla_lin > bnd_lin > hydr_lin > city_pnt > mt_lin > feature > The dataset also includes an ARC/INFO AML, lineset, and markerset that will produce the EPS file of the geology and glacial features. Entity_and_Attribute_Detail_Citation: The gla_net coverage includes polygons that are units of glaciation and open water, and arcs that are limits of glaciation, color boundaries, and shoreline. The gla_net.pat INFO file consists of the following user-defined items: TEXT--Is a two-letter symbol for the map unit, which refers to the age and type of glacial deposit represented by the polygon or 'la' for a water body. MAP_UNIT--A brief description of the map unit represented by TEXT. COLOR--An integer value representing a shade pattern in the shadeset color524.shd used in preparing the graphic of the map. Items in gla_net.pat are defined as follows: > >TEXT MAP UNIT COLOR > VALLEY GLACIAL DEPOSITS >LP Late Pinedale till 171 >MP Middle Pinedale till 413 >EP Early Pinedale till 449 >LB Late Bull Lake till 160 >EB Early Bull Lake till 185 >BL Bull Lake till, undivided 146 >KD Kennedy drift 493 > > PIEDMONT GLACIATION GLACIAL DEPOSITS (OUTLET DEPOSITS OF > GLACIERS FROM THE NORTHERN MONTANA ICE FIELD) >P3 Pinedale 3 till 370 >P2 Pinedale 2 till 59 >P1 Pinedale 1 till 449 > > CONTINENTAL GLACIAL DEPOSITS >LW Late Wisconsin till 407 >IL Illinoian till 54 >PW Pre-Wisconsin tiil and > glacial erratic boulders 400 >PI Pre-Illinoian till (Pleistocene) 209 >GB Pre-Illinoian glacial erratic boulders > on eroded bedrock (Pleistocene) 127 > >ng Not glaciated 0 >lake Lake 0 > The gla_net.aat INFO file consists of the following items: CODE--A one- or two-digit number representing a particular glacial limit, shoreline, scratch boundary, or map boundary LTYPE--A text description of the CODE Items in geo_net.aat are defined as follows: >CODE LTYPE > >0 lake, river, or stream shoreline > > VALLEY GLACIATION >1 limit of late Pinedale glacial advance >2 limit of middle Pinedale glacial advance >3 limit of early Pinedale glacial advance >4 limit of late Bull Lake glacial advance >5 limit of early Bull Lake glacial advance >6 limit of Bull Lake till, undivided >7 limit of pre-Bull Lake Kennedy drift > > PIEDMONT GLACIATION >8 limit of Pinedale 3 glacial advance >9 limit of Pinedale 2 glacial advance >10 limit of Pinedale 1 glacial advance > > CONTINENTAL GLACIATION > LATE WISCONSIN >11 limit of late Wisconsin glaciation >12 limit of late Wisconsin glaciation, inferred >27 limit of "C2" regional glacial readvance in southwestern Alberta >13 limit of a late Wisconsin regional glacial readvance >14 limit of a late Wisconsin ice-margin readvance or stillstand > > ILLINOIAN >17 limit of Illinoian glaciation >18 limit of Illinoian glaciation, inferred >19 buried limit of Illinoian glaciation >20 limit of a major Illinoian ice-margin readvance > > PRE-WISCONSIN >22 limit of pre-Wisconsin till and glacial erratic boulders > > PRE-ILLINOIAN (PLEISTOCENE) >23 southern limit of pre-Illinoian Pleistocene till on north flank of > Bearpaw Mtns. >24 buried limit of pre-Illinoian Pleistocene till >25 limit of pre-Illinoian glacial erratic boulders on eroded bedrock >30 scratch boundary >61 map boundary The gla_lin line coverage contains boundaries of glaciation and other buried features. The gla_lin.aat INFO file consists of the following items: CODE--A one- or two-digit number representing a particular glacial limit LTYPE--A text description of the CODE items in geo_lin.aat are defined as follows: >0 Buried glacial features, including Margin of Charbonneau Sag, > Margin of Culbertson Sag, Margin of Guardipee Lake Spillway, > Margin of Shonkin Sag channel, Margin of buried valley of > ancestral Missouri River, and Margin of buried valley of > ancestral Yellowstone River. > VALLEY GLACIATION >1 limit of late Pinedale glacial advance >2 limit of middle Pinedale glacial advance >3 limit of early Pinedale glacial advance >4 limit of late Bull Lake glacial advance >5 limit of early Bull Lake glacial advance >6 limit of Bull Lake till, undivided >7 limit of pre-Bull Lake Kennedy drift > > PIEDMONT GLACIATION >8 limit of Pinedale 3 glacial advance >9 limit of Pinedale 2 glacial advance >10 limit of Pinedale 1 glacial advance > > CONTINENTAL GLACIATION > LATE WISCONSIN >11 limit of late Wisconsin glaciation >12 limit of late Wisconsin glaciation, inferred >27 limit of "C2" regional glacial readvance in southwestern Alberta >13 limit of a late Wisconsin regional glacial readvance >26 limit of a late Wisconsin regional glacial readvance, inferred >14 limit of a late Wisconsin ice-margin readvance or stillstand >15 limit of a late Wisconsin ice-margin readvance or stillstand, inferred >16 limit of a major late Wisconsin glaciotectonic deposit or structure > > ILLINOIAN >17 limit of Illinoian glaciation >18 limit of Illinoian glaciation, inferred >19 buried limit of Illinoian glaciation >20 limit of a major Illinoian ice-margin readvance >21 limit of an Illinoian ice-margin readvance or stillstand > > PRE-WISCONSIN >22 limit of pre-Wisconsin till and glacial erratic boulders > > PRE-ILLINOIAN (PLEISTOCENE) >23 southern limit of pre-Illinoian Pleistocene till on north flank > of Bearpaw Mtns. >24 buried limit of pre-Illinoian Pleistocene till >25 limit of pre-Illinoian Pleistocene glacial erratic boulders on > eroded bedrock > > The bnd_lin coverage is a map boundary and 2° projection lines within it. The bnd_lin.aat INFO file consists of the following item: CODE--Is a two-digit number representing the type of line and is defined as follows: > >CODE TYPE OF LINE >61 Map boundary >62 Projection line The hydr_lin coverage is a line coverage that shows selected hydrographic features within the map boundary. The hydr_lin.aat INFO file consists of the following three user-defined items: FEATURE--A description of the type of feature described by the line and is one of the following: "Dam", "Left Bank", "Right Bank", "Shoreline", or "Stream". NAME--The name of the feature and is one of the following: > Belly River > Big Muddy Lake > Bow River > Cut Bank Creek > Cypress Lake > Downie Lake > Fife Lake > Fort Peck Dam > Fort Peck Lake > Frazer Lake > Fresno Dam > Fresno Reservoir > Hungry Horse Reservoir > Judith River > Junction Reservoir > Keho Lake > Lake Frances > Lake Sakakawea > Lake of the Rivers > Little Missouri River > Marais River > Middle Creek Reservoir > Milk River > Missouri River > Montague Lake > Murray Lake > Musselshell River > Newton Lake > Oldman Lake > Oldman River > Poplar River > Saint Mary Reservoir > Saint Mary River > South Saskatchewan River > Teton River > Thomson Lake > Tiber Dam > Tiber Reservoir > Twelve Mile Lake > Waterton Lake > Waterton Reservoir > Waterton River > West Coteau Lake > Willow Bunch Lake > Yellowstone River STATE--The state where the feature exists in the United States and is > either "MT" or "ND" or the province in Canada and is either 'AB' > or 'SK'. > City_pnt is a point coverage containing cities within the United States area of the map. The city_pnt.pat INFO file contains the user-defined items "NAME" and "STATE". The feature coverage is a point coverage of cities in Canada and a few selected points of interest that are described in the text. The feature.pat INFO filecontains the item "NAME" as the only user-defined item. In addition to city names, it also contains the names of locations of stratigraphic sections (Milk River Ridge, Mokowan Butte, Two Medicine Ridge, and St. Mary Ridge), the location of erratic blocks from the Canadian Shield, and the location of a Lava Creek B volcanic ash site. The MT_lin coverage is a line coverage of the state and province boundaries within the map area. The mt_lin.aat INFO file contains the user-defined item "CODE" which has the following values: >CODE Value >2 Montana/North Dakota boundary >3 Alberta/Saskakatchewan boundary >4 United States/Canada boundary Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: Mailing address Address: Central Publications Group, MS902, Box 25046, Denver Federal Center City: Denver State_or_Province: CO Postal_Code: 80225 Country: USA Contact_Voice_Telephone: (303) 236-4845 Contact_Facsimile_Telephone: (303) 236-6287 Contact_Electronic_Mail_Address: tpinto@usgs.gov Resource_Description: Scientific Investigations Map 2843, Map Showing Spatial and Temporal Relations of Mountain and Continental Glaciations on the Northern Plains, primarily in Northern Montana and Northwestern North Dakota. Distribution_Liability: Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this data set has been used by the U.S. Geological Survey, no warranty, expressed or implied, is made by the USGS as to the accuracy and functioning of the data set and related material nor shall the fact of distribution constitute any such warranty, and no responsibility is assumed by the USGS in connection therewith. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: ARCE Format_Version_Number: 7.2.1 File_Decompression_Technique: WinZip (Windows), Gzip compressed TAR archive (UNIX) Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: Fees: No cost for the digital files. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: ESRI Shapefile Format_Version_Number: 7.2.1 File_Decompression_Technique: WinZip (Windows), Gzip compressed TAR archive (UNIX) Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: Fees: No cost for the digital files. Technical_Prerequisites: ARC/INFO 7.2.1 Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: Mailing Address: U.S. Geological Survey Information Services, Box 25286, Denver Federal Center City: Denver State_or_Province: CO Postal_Code: 80225 Country: USA Contact_Voice_Telephone: 1-888-ASK-USGS Resource_Description: Scientific Investigations Map 2843, "Map Showing Spatial and Temporal Relations of Mountain and ContinentalGglaciations on the Northern Plains, Primarily in Montana and Northwestern North Dakota (printed edition). Distribution_Liability: Although this data set has been used by the U.S. Geological Survey, no warranty, expressed or implied, is made by the USGS as to the accuracy and functioning of the data set and related material nor shall the fact of distribution constitute any such warranty, and no responsibility is assumed by the USGS in connection therewith. Standard_Order_Process: Non-digital_Form: Available as one folded sheet, printed on a four-color press and pamphlet; order from USGS at address listed above. Fees: Call 1-888-ASK-USGS for price of printed edition or http://mapping.usgs.gov/esic/prices. Metadata_Reference_Information: Metadata_Date: 20040801 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Charles A. Bush Contact_Organization: U.S. Geological Survey Contact_Position: Emeritus Geophysicist Contact_Address: Address_Type: Mailing Address: U.S. Geological Survey, MS913, Box 25046, Denver Federal Center City: Denver State_or_Province: CO Postal_Code: 80225 Country: USA Contact_Voice_Telephone: (303) 236-4723 Contact_Facsimile_Telephone: (303) 236-0214 Contact_Electronic_Mail_Address: cbush@usgs.gov Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Access_Constraints: none Metadata_Use_Constraints: none