The phenocryst compositions were determined for representative samples from the six igneous units defined from Transect EG68. Microprobe results for coexisting plagioclase and clinopyroxene phenocrysts are presented in "Appendix B" of the "Explanatory Notes" chapter and summarized in Table T3. Olivine suitable for microprobe analysis was not present in thin section (cf. Fig. F5B). Plagioclase compositions range from An73 to An83 , whereas clinopyroxene is augitic with Mg numbers from 0.78 to 0.81. Whole-rock and clinopyroxene Mg numbers are positively correlated.