Early in "Smurfs That Time Forgot: Part 1," the Smurfs found a frozen triceratops hidden in a mountain after Brainy unintentionally cause an avalanche. Since the triceratops lived during the Mesozoic era, where the Earth is much warmer than it is today (and the landmass centered near the Equator millions of years ago), it is not possible for ice to appear on land or for any creature from that era to be encased in it.
You don't see Wild Smurf or Baby Smurf anywhere until they've gone back time and they keep disappearing in other upcoming episodes.