Validator: How to settle this error?

I get this error in the validator:

Line 47, Column 187: character "&" is the first character of a delimiter but occurred as data 
…num, silver diamonds. cartier tiffany & Co.  $18 WALKING LIBERTY DOLLARS   $15…



This message may appear in several cases: 
You tried to include the "<" character in your page: you should escape it as "&lt;"
You used an unescaped ampersand "&": this may be valid开发者_如何学C in some contexts, but it is recommended to use "&amp;", which is always safe.
Another possibility is that you forgot to close quotes in a previous tag.

How to settle it?

You forgot to escape an ampersand.

Replace & with &.