Here are two sources from the guide that tell more about U.S. junk silver.
The Junk Silver Coins page gives a breakdown of how much silver is in each coin and how to calculate for yourself how much each coin is worth, plus the page shows images of all the individual U.S. junk silver coins and their circulated mintages.
The Junk Silver Buying Guide page - is a buying guide that offers more information than the page above, which also helps you in what to look for in junk silver and how they are sold.