Sauropod stones

["Norton, Patrick" <Patrick.Norton@state.me.us>]

References for works on the use of light scattering to distinguish   
between gastroliths and non-gastroliths are posted below. The general   
conclusion from these articles is that the degree of polish on   
gastroliths is measurably different, using light scattering techniques,   
from that of stream polished rocks. The causes of the higher polishing is   
not investigated, but the contribution of digestive acids is suspected to   
play a role along with abrasion during gizzard contractions.

JOHNSTON, R.G., K. MANLEY, and C.L. LEMANSKI. 1990. Characterizing   
gastrolith surface roughness with light scattering. Optics   
Communications, 74:279-283.

MANLEY, K. 1991. Two techniques for measuring surface polish as applied   
to gastroliths. Ichnos, 1:313-316.

MANLEY, K. 1993. Surface polish measurement from bona fide and supsected   
dinosaur gastroliths and wave and stream transported clasts. Ichnos.   
2(2):167.

JOHNSTON, R.G., W.G. LEE and W.K. GRACE. 1994. Identifying Moa   
gastroliths using a video light scattering instrument. Journal of   
Paleontology. 68(1):159-163.