Vehicular rearview mirror assembly

A vehicular exterior rearview mirror assembly includes a mirror head adjustably disposed at a mounting structure. An electro-optic reflective element is attached at an attachment element that attaches at an electrically powered actuator disposed in the mirror head. The attachment element includes a protruding portion that is at least partially received at a notched region of the rear glass substrate when the reflective element is disposed at the attachment element. An outer surface of the protruding portion of the attachment element corresponds with the second perimeter edge of the rear glass substrate at the notched region of the rear glass substrate. With the electro-optic reflective element disposed at the mirror head, the outer surface of the protruding portion provides a curved transition from an outer surface of the mirror head toward the first surface of the front glass substrate.