Complex sentence: MacAllister suggests this indentation is a survival of the observation-notch which at one time must have adorned the edges of shields but supports an alternative explanation that this interruption of circular ornament may reflect the taboo and widespread superstition against closed rings.
Split into simpler sentences: MacAllister suggests this indentation is a survival of the observation-notch which at one time must have adorned the edges of shields. Alternatively, this interruption of circular ornament may reflect a taboo and widespread superstition against closed rings.