I was MDing last weekend, here in Ottawa region, on one local beach. Found bunch of coins (mainly pennies). Coins are from KGVI era to modern times. Among others, I've spotted one weird corroded coin which attracted my attention by little bit smaller diameter (about 0.8mm less than normal) and distinctive outer rim. As well as under magnification noticed complete absence of the small dots (ruling?) on the perimeter under the rim. Other details of design differ as on me as well. I know almost nothing about Canadian coins, so it would be great to hear suggestion from fellow community members. Please see the pictures below. I placed couple pennies on the left and right for comparison (they were found in the same time on the beach).