There are three files to download per quad:
xxxxxx.sdw
xxxxxx.sid
xxxxxx.txt

Click here for DRG's

Click here for DOQQ's
3390A1 LEXINGTON SOUTH
3390A2 HOWARD
3390A3 THORNTON
3390A4 SILVER CITY
3390A5 MIDNIGHT
3390A6 RICHEY
3390A7 DELTA CITY
3390A8 PERCY
3390B1 LEXINGTON NORTH
3390B2 TCHULA
3390B3 MARCELLA
3390B4 BELZONI
3390B5 BELLEWOOD
3390B6 MIDNIGHT NW
3390B7 HOLLANDALE
3390B8 SWAN LAKE NW
3390C1 BLACK HAWK
3390C2 CRUGER
3390C3 MONTGOMERY
3390C4 SWIFTOWN
3390C5 INVERNESS
3390C6 KINLOCK
3390C7 TRIBETT
3390C8 ARCOLA
3390D1 GRAVEL HILL
3390D2 SIDON
3390D3 ITTA BENA
3390D4 COLONY TOWN
3390D5 MOORHEAD
3390D6 INDIANOLA
3390D7 HOLLY RIDGE
3390D8 LELAND
3390E1 BROWNING
3390E2 GREENWOOD
3390E3 SHELLMOUND
3390E4 BEAR GUT BAYOU
3390E5 SUNFLOWER
3390E6 BOYER
3390E7 SHAW MS
3390E8 STRINGTOWN
3390F1 AVALON
3390F2 MONEY
3390F3 SCHLATER
3390F4 RATTLESNAKE BAYOU
3390F5 RULEVILLE
3390F6 CLEVELAND
3390F7 SKENE
3390F8 LOBDELL
3390G1 CASCILLA
3390G2 PHILIPP
3390G3 GLENDORA
3390G4 BROOKS
3390G5 DREW
3390G6 MERIGOLD
3390G7 PACE
3390G8 BEULAH
3390H1 PAYNES
3390H2 TIPPO
3390H3 WEBB
3390H4 ROME
3390H5 BALTZER
3390H6 MOUND BAYOU
3390H7 SHELBY
3390H8 GUNNISON