These are Chinese cash coins. They have been made for hundreds of years. Yours is probably about 200 years old. I found one earlier this year. If you look them up on the net you can get a date range.
Smokey is right. Coin with the hole is Chinese, and they are pretty plentiful here in the U.S., especially if you hunt in the fields. You mentioned your Merc is a 1916. Flip that thing over, and see if it has the D Mint mark. If so, you found a good one. There were only 264,000 of those minted.