The zonal arrangement, with minor modification, follows that described by Cameron et al. (1949). Simple pegmatites are considered to form by local secretion at an early stage in the metamorphism. 'Complex pegmatites are genetically related to late-tectonic granite plutons intruded into environments of moderate- to high-grade metamorphism.' In general, when similar granites are intruded at higher crustal levels, they crystallize more quickly, and their unusual elements are not concentrated; tin mineralization is an exception to this generalization.

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