Since Version 2.0 (released in 1991), CellArray has been superseded by Raster and RasterArray.
As of Mathematica 7, ChebyshevDistance is superseded by ChessboardDistance.
ColumnForm has been superseded by the more general function Column.
Compose
(Obsolete Mathematica Symbol) Since Version 2.0 (released in 1991), Compose has been superseded by Composition.
Since Version 5.0 (released in 2003), ConstrainedMax has been superseded by Minimize, Maximize, NMinimize, and NMaximize.
Since Version 5.0 (released in 2003), ConstrainedMin has been superseded by Minimize, Maximize, NMinimize, and NMaximize.
Since Version 2.0 (released in 1991), ContourLevels has been superseded by Contours.
As of Version 6.0, ContourLines has been superseded by settings for ContourStyle.
Since Version 2.0 (released in 1991), ContourSpacing has been superseded by Contours.
As of Version 6.0, ConversionOptions is superseded by capabilities in Import and Export.