LAKE CHARLES, LOUISIANA/TEXAS 30 x 60 MINUTE GEOLOGIC QUADRANGLE SERIES 94°00' 45' 30°30' NEWTON CO 30' 15' 93°00' Pp 30°30' Pp k Description of Map Units e Hsm Pil Hua Pil e Pil Ppbe r C Ppbe Hb Hua Pil Ppbe HOLOCENE Ppbe r Beckwith a BEAUREGARD PARISH Hua e Ppbe B Ppbe Holocene unnamed alluvium, undifferentiated—alluvial deposits of minor streams Pil Pil Hua Hua and creeks filling valleys cut into older deposits. The modern flood plain within these valleys constitutes the surface of the deposits. The lithology of these alluvial deposits reflects the De Quincy reworked lithology of their adjacent source. Pil Hua Pil Ppbe Small river deposits, undifferentiated—undifferentiated alluvium of small coastal Ppbe Pil Hua rivers, consisting of recognizable but unmapped channel and overbank deposits within the Ppbe Pd Ppbe Hs Calcasieu River valley. Pil Pio Hsm Hua Pd Small river meander-belt deposits—point-bar and associated overbank deposits Ppbe Hsm underlying meander belts of the Sabine River. The surface of the meander belt. Is Pil Pd Hs characterized by ridge and swale topography. These deposits typically consist of gray to Ppbe Pd reddish brown sand, silt, silty clay, and sandy clay. Pd —Fine-grained Holocene backswamp deposits of the Sabine River, Pil Backswamp deposits Hb underlying flood basins between meander belts. These sediments consist of dark reddish RIVER Pil Ppbe Ppbe Pd brown to dark gray or black silty clay or clay. Ppbe Litt Pd le Ppbe Bayou Pil M Mermentau Alloformation—Complexly interfingering and interbedded, dark-colored a Pil rs Hm marine muds, sandy and shelly beach deposits, organic marsh clays, and lacustrine and bay Pd h ALLEN PARISH Ppbe Ppbe muds. These deposits bury the surfaces of the Prairie and Deweyville Allogroups. The U B Hs U a U y JEFFERSON DAVIS PARISH Louisiana chenier plain forms the surface of the Mermentau Alloformation. The Hsm D Hua o Hua Pil D D u Pio Ppbe Alloformation extends westward along the coast into Texas as far west as Galveston Bay. Ppbe Hua Hua Eastward, it extends almost to the west shore of Vermilion Bay, where it interfingers with U Ppbe Ppbe Pds Pil Pd deltaic sediments of the Teche delta lobe. Seaward of the shoreline, the Mermentau Hua D eek Marsh Alloformation grades laterally into unnamed marine sediments. BEAUREGARD PARISH Pil Cr Hua Ppbe Hua Hua BEAUREGARD PARISH Pd Ppbe CALCASIEU PARISH U Ppbe CALCASIEU PARISH Bayou Hb D Hua RIVER PLEISTOCENE Ppbe Pil Pil Pdm Pil Ppbe Hua Ppbe DEWEYVILLE ALLOGROUP SABINE U Pd Hs Ppbe D Ppbe Pil Ppbe Pil Pd Deweyville Allogroup, undifferentiated—alluvial deposits of ancestral late Pleistocene Pil Pio Pd coastal plain streams and certain Mississippi River tributaries. In the Lake Charles Pil Ppbe Pil Ppbe Ppbe Pds Pil Pil quadrangle, these include the Sabine and Calcasieu river valleys. Multiple levels are locally Hua Hb U Pil Ppbe recognized and delineated where applicable. Surface morphology can be veneered by Hsm Hua Ppbe D Ppbe younger alluvium. The surface of the Deweyville Allogroup is topographically inset into the Ppbe Ppbe Prairie Allogroup or older deposits and is characterized by meander scars substantially Pil Ppbe Pd Indian Ppbe Hs larger than those of modern stream flood plains. Surface deposits are generally sandy and Ppbe Hua grade to sandy and gravelly channel and point-bar deposits. Ppbe Little Serpent you Ppbe Pil Ba Ppbe Fredonia alloformation—youngest alloformation and topographically lowest surface of Ppbe Pdf the Deweyville Allogroup along the Sabine River. It lies near the level of the Sabine River Pil Ppbe dian Hua Pdm Pd In flood plain and is mostly buried by it. At Deweyville, Texas, the Fredonia alloformation lies Ppbe Pil Hua e at the level of and is largely buried by sediments of the Sabine River flood plain. tl it L Bayou Buxton Pd CALCASIEU Sandjack alloformation—alloformation of the Deweyville Allogroup along the Sabine Pil Ppbe Pd Pds River that is intermediate in age and topographic position between the Merryville and Hb Hua Pil Fredonia alloformations. Deweyville Texas lies on the surface of the Sandjack alloformation. LOUISIANA Ppbe Ppbe Hsm Ppbe Hs —oldest alloformation and topographically highest surface of the Ppbe Merryville allformation Hb Ppbe Ppbe Pdm Deweyville Allogroup along the Sabine River. The terrace of the Merryville alloformation Hsm Ppbe Ppbe River lies on the Louisiana side of the Sabine River Valley directly across from Deweyville, Texas. Hua Ppbe Ppbe Hua Pd Ppbe TEXAS Ppbe Arceneaux Pdm River Houston Hua Hua Ppbe PRAIRIE ALLOGROUP Ppbe Hua Bayou Ppbe Hs Prairie Allogroup, undifferentiated—a diverse depositional sequence of late to middle Pp Pleistocene deposits of the Mississippi River, its tributaries, and coastal plain streams. Pdf Ppbe Ppbe Ppbe Hua Ppei Houston Ppei Includes terraced fluvial (meander belt, backswamp, and braided-stream), colluvial, estuarine, JASPER CO Hua Ppei Pd NEWTON CO Ppei Ppei deltaic, and marine units deposited over a considerable interval of the late Pleistocene Deweyville Ppei Ppei Hsm (Wisconsin to Sangamon). Surfaces generally show little dissection and are topographically Ppei Moss Bluff Ppbe Hs Ppbe River Pd higher than the Deweyville. Multiple terrace levels are recognized along alluvial valleys and Ppei Hua Pd coast-parallel trends. The Prairie is locally mapped as undifferentiated alluvial terraces Hs Ppbe Ppbe Hua where discontinuous surfaces are incised into older allogroups within valleys. The allogroup Pd Hs is divided into two temporal depositional phases: Late Sangamon and Early Sangamon

Prairie Allogroup, Early Sangamon—a diverse depositional sequence of flood plain, Ppbe Hs meander belt, and backswamp deposits of the middle Pleistocene ancestral Mississippi River, Red River, local fluvial equivalents of tributary streams, and coastal plain streams. English Older and topographically higher of the Prairie Allogroup temporal phases. Where this unit Hb Ppbe Pd Pdm is mapped near the Mississippi River flood plain, it is blanketed by both Peoria and Sicily

Island Loess or by loess-derived colluvium. The unit dips into the subsurface beneath the CALCASIEU PARISH CALCASIEU Pd Bayou Pleistocene Prairie Allogroup, Late Sangamon in the coast-parallel region, but is commonly Hsm Ppbe Hs PARISH DAVIS JEFFERSON terraced above it in stream valleys. The sediments are generally clay, silty clay loam, or sandy clay loam and grade to sand and gravel. Hua 15' Sulphur Beaumont Alloformation—coastal plain deposits of late to middle Pleistocene West Lake 15' Ppbe streams; the oldest alloformation and topographically highest surface of the Prairie Hs Ppbe Allogroup units of southwestern Louisiana. It exhibits the relict channels of the Red Ppbe Ppbe Hs and Calcasieu rivers, and includes deposits of the Ingleside barrier trend within the ORANGE CO Lake Charles quadrangle.

relict Pleistocene coastal ridges—low-lying ridges delineated on the surface of Pdm Pper the Beaumont Alloformation. Some of these ridges are coast-parallel and others Ppbe Maplewwod Lake trend obliquely to the coast and radiate from the end of known meander belts. In U Charles the southeast portion of the Lake Charles quadrangle, limited drilling indicates that Hs D these ridges are either meander-belt ridges or deltaic distributaries of differing ages. The origins of other coastal ridges within the Lake Charles quadrangle remain Hb Ppbe Hsm undetermined. Ppbe Hollywood Lake relict Pleistocene barrier ridge (Houston ridge)—eastern segment of the Hua Hs Charles Ppbe Ppei Ingleside barrier trend of Texas; ridge delineated on the surface of the Beaumont Pds Ppbe Ppbe Hs Pper Alloformation. Hs Hsm Vinton Pdm Pper INTERMEDIATE ALLOGROUP Pper Ppbe Intermediate allogroup, undifferentiated—fluvial deposits of the Sabine and Calcasieu Hs Rivers, their tributaries, and coastal plain streams. The deposits of the Prairie Allogroup Pds onlap the surfaces of the Intermediate allogroup within the Lake Charles quadrangle. CALCASIEU SHIP CHANNELPrien Lake Within the DeRidder quadrangle to the north, the surfaces of the Intermediate allogroup lie Ppbe Pds below the topography of the adjoining Upland allogroup and Tertiary formations. The Ppbe Pper Intermediate allogroup surfaces are generally dissected and lack distinct constructional topography. The Intermediate is locally mapped as undifferentiated alluvial terraces where Hb Prien discontinuous surfaces are incised into older allogroups within valleys. Hsm Ppbe Pds Oakdale alloformation—alluvial deposits of middle Pleistocene streams in Ppbe Pper Pio southwestern Louisiana, lying in elevation below the higher surfaces of the Hb Pper Intermediate and Upland allogroups and above the Prairie Allogroup, Early Ppbe Sangamon. The surface is highly dissected and lacks any constructional Hs Ppbe topography. Near the Mississippi River flood plain, the unit is blanketed by Sicily Vidor Pper Pdm Island Loess, which is overlain by less than 1 meter of Peoria Loess in places Ppbe southwest of where the flood plain is joined by that of the Red River. Previously it Ppbe has been designated as the Oberlin surface in southwestern Louisiana. Hua Pper Lissie Alloformation, undifferentiated—dissected alluvial deposits of early Pper Pil Hs Ppbe Pleistocene streams. The regionally extensive Upland geosol occurs at the top of the unit. The unit is bounded updip by the Willis Formation and downdip by Hb Ppbe Ppbe younger subunits of the Intermediate allogroup and the Prairie Allogroup. Near the Pper Mississippi River flood plain, the unit is blanketed by Sicily Island Loess. Ppbe Pper Moss Recognition in the area encompassing the Lake Charles quadrangle is facilitated by Hsm Lake Orange Pdm Ppbe Hm the subregionally extensive De Ridder surface. Within the Lake Charles quadrangle, the Dequincy fault-line scarp offsets the surface of the Lissie Alloformation. Previously designated as the Bentley terrace in southwestern Ppbe Louisiana. Ppbe Pdm Pper U Hs Pper Ppbe Pdm D Ppbe RIVER Pper Open Water Hua Hm Hm Ppbe Hb Ppbe Contact—dashed where inferred. Hsm Pper Ppbe Ppbe Hua Fault—dashed wher e inferred; dotted where concealed. Ppbe Pper Clear Pper Ppbe Marais Hs INTRACOAST Hua Ppbe Ppbe Streams Hs Hm Ppbe Pper AL Hsm Hua Topographic contours Ppbe Hs Pper Ppbe Pper Roads Hm Hm Pper Hm Hua Y Hs Railroads A INTRACOASTAL Hm WATERWAY Pper Pper

W Hm Ppbe Hm R Hs Ppbe Area uplifted by salt dome E CALCASIEU PARISH T Pper Ppbe A W CAMERON PARISH Ppbe Hs Pper Ppbe Ppbe Ppbe CALCASIEU PARISH Hsm Hm Hm W Hua A Ppbe TERW CAMERON PARISH AY NECHES RIVER Hm Hua CALCASIEU AL Ppbe ke Hm Ppbe T La Ppbe Pper Pper S LAKE Ppbe A Hm ck O ayou la Hm Pper C B B A k Ppbe R c Hm Ppbe la Ppbe T B Ppbe N SABINE I Hm U 30°00' Ppbe Hm Ppbe Ppbe Hm Hm 94°00' D 45' 30°00' 30' 15' 93°00 94° 92° 90° Produced and published by the Louisiana Geological Survey 208 Howe-Russell Geoscience Complex, Louisiana State University Kilometers 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 LAKE CHARLES, LOUISIANA/TEXAS P.O. Box G, Baton Rouge, LA 70893 • 225/578-5320 • www.lgs.lsu.edu 30093-A1-TM - 100K Miles 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 Production of this map was supported by the U.S. Geological Survey, Correlation of Map Units L O U I S I A N A Department of the Interior under Assistance Award No. 1434-HQ-96-AG-01490. 32° SCALE 1:100,000 Sabine Calcasieu coastal plain 0 50 miles River valley River valley Base map from U.S. Geological Survey 1:100,000 Digital Line Graphs (100K DLG) Universal Transverse Mercator Projection, Zone 15 Hsm Hb Hs Hua Hm Copyright ©2002 by the Louisiana Geological Survey 1927 North American Datum (NAD 27)

Contour Interval 10 meters Pdf De Ridder Ville Platte New Roads Amite Bogalusa National Geodetic Vertical Datum 1929 Pds Pd The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either Lake Charles Crowley Baton Rouge Ponchatoula Gulfport Pdm expressed or implied, of the U.S. Government or the state of Louisiana. Geology by: 30° 1934 Ppei Pper Paul Heinrich, John Snead, and Richard P. McCulloh This map has been car efully prepared from the best existing sources available at the Pp Ppbe Chacko J. John time of preparation. However, the Louisiana Geological Survey and Louisiana State GIS compilation by: Director & State Geologist University do not assume responsibility or liability for any reliance thereon. This R. Hampton Peele, Edwin Millet, Vishweshwar Admal, Anuradha Eragani, Swathi Kambalapally, information is provided with the understanding that it is not guaranteed to be correct 30 x 60 Minute Geologic Quadrangles Lake Charles 30 x 60 Minute Geologic Quadrangle Pio Pratyush Kumar, and Weiwen Feng or complete, and conclusions drawn from such data are the sole responsibility of the user. These regional geologic quadrangles are intended for use at the scale of Published (2002) Pil 1:100,000. A detailed on-the-ground survey and analysis of a specific site may differ Cartography by: In preparation 2002 from these maps. Edwin Millet and John Snead