By far the commonest lamellar structures occurring in calcite of Yule marble deformed at 20° to 300°C are parallel to forumla. Some of these are recognizable as twin lamellae, but many lack definite criteria of twinning. Three types of anomalous lamellae, differing distinctly from forumla in their angular relations to [0001] and to other recognizable lattice directions, are also common in some deformed specimens. Lamellar structures parallel to forumla and forumla and cracks subparallel to forumla have also been noted.

This paper summarized information as to criteria (appearance and crystallographic orientation) for recognition of the various types of lamellae, and the stress environments in which each tends to develop. A synopsis of this information is appended (Table 2).

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