- Brilliancy, relative, of Mars
- Brontes, the
- Calendar, the Martian
- Canals
- Canals
- Canals (and pages following this)
- straightness of
- breadth of
- length of
- length of
- history of
- doubling of
- duplication of
- duplication of (and pages following this)
- catalogue of
- number of
- not natural features
- not natural features
- changes in
- changes in
- changes in
- changes in
- constitution of
- constitution of
- in dark regions
- in dark regions
- in dark regions (and pages following this)
- at times invisible
- list of, in dark regions
- Carbonic acid gas
- Carbonic dioxide. (See Carbonic acid gas)
- Cassini, rotation of Mars
- Causeways
- Ceraunius, relative visibility of
- Changes, on disk
- Changes, on disk
- in tint of land areas
- in tint of land areas (and pages following this)
- in tint of land areas
- in canals
- in canals
- in canals