Catalogue entry no. 626 by Max Loehr:
626 Arc-shaped Tablet with Bird Figure
Opaque mottled green and black hard-stone segment, possibly recarved from a broken disk. Part of the outer circumference is wrought into a sequence of serrate formations. A single formation of this kind projects from the rear of the awkwardly shaped bird’s head at the upper end of the tablet. Except for a minute notch below the tip of the wing, none of the bird’s remaining parts is expressed in the contour of the tablet. The wings, the tail, and the thin-clawed feet are indicated by raised lines, as are the eyes, which intrude upon the beak, and the spirals that fill the large and empty surface behind the eyes. Near the obtuse point of the plain, haphazardly cut-off lower end is a perforation that was drilled from both sides. Although this object might not be rejected on technical grounds alone, its undeniable lack of organic feeling and artistic form makes it impossible to group it among Shang or early Chou material. The discrepancy between the lapidary skill and the formal imperfection is puzzling, and is cause enough, I believe, to leave the date open.
