6. You should capitalize geographical features when part of the official name. In the plural capitalize them when they precede names but do not when they follow

a. The Gobi Desert is in Xinjiang province.
b. The Sahara desert can be a hot place.
c. The Yangzi and Yellow rivers flow from west to east.
d. Recently Lakes Erie and Ontario have been popular for boating.

7. Capitalize points of the compass when you use them as part of section of the country, otherwise do not capitalize them.

a. Go east from here to see the river.
b. She loves to travel in the South but doesn't like the North.
c. She lives in southern California.