Preferred orientation patterns are recorded for c axis, a1, a2, a3 axes, forumla lamellae, edges [e:é] between prominent forumla lamellae, and forumla lamellae in Yule marble deformed to various degrees in the laboratory at 10,000 atmospheres confining pressure, room temperature, dry. The changes of fabric observed correspond strikingly with those predicted by Handin and Griggs (Part II) on their hypothesis of homogeneous deformation.

Visible forumla lamellae can be correlated with gliding (probably twinning) in the direction and sense appropriate for twinning. Translation on forumla in the opposite sense, though effective in many cases, leaves no microscopically visible trace. Gliding in the twinning sense on forumla could account for development of relatively insignificant lamellae.

Comments are added regarding interpretation of petrofabric data in general, in the light of the results here recorded.

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