'Anachronism' refers to an object or thing which belongs to a time period which is not the one it is being referenced in. For example, when considering a medieval village, one would not consider...
Halloween night I saw a fake snow man in some one's yard, how anachronism.
We no longer travel by horse and buggy; They have now become an anachronism.
The answer is the anachronism myth.
The anachronism of reading that there was a clock during the time of the Pilgrims coming to the Americas really made me chuckle.