IMMEDIATELY north of the village of Karacayir, vilayet Sivas, Turkey, a small intrusion of rather coarse-grained syenite occurs in a banded marble formation of unknown age. Here I had occasion to study in some detail a peculiar coarse-grained marble of pegmatitic appearance, containing biotite and apatite. The banded marbles seem to be regionally metamorphosed, on which the thermal metamorphism caused by the intrusion is superimposed. The part of the marble which protrudes into the syenite is changed into a carbonatite–pegmatite. Otherwise the marbles retain their regular banding, which even seems to be accentuated when nearing the contact. Within the aureole of thermal metamorphism small crystals of phlogopite and diopside develop in small amounts on the stratification planes as well as throughout the marble. Near the contact small dikes of syenite–aplite and more-or-less crushed syenite–pegmatite cut through the marbles; the syenite itself contains locally muscovite.