Research about small foraminifera in the bottom part of Kebo Butak formation is not many yet to do.Therefore, researchers conducted to study on the subject by taking the research area in Kalinampuand surrounding area of Bayat Klaten Central Java. The choice of location because the areacontained Nampurejo pillow lava which have been considered as the base of the sediment Kebo Butak formation. Research methodology is by measuring stratigraphy to get vertical pattern and geologicalmapping to determine the lateral spread of rock.. Fasies of rock in the study area devide into nine facies. Measurement track devide into three line. Line of Kalinampu-Sendangrejo devide into 13biozonation starting from Globigerinatheka subconglobata curryi zone (P11) and finishing withGlobigerina binaensis
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Globigerina venezuelana zona (N5). Line of Sumberan-Mojosari divided into7 biozonasi starting with Globorotaloides carcoseleensis zone (P14) and finishing with Globorotaliaopima nana zone (N2). Line Mranggen-Dukuh be clear boundaries between zones but in the fossil samples contained DN/DKH/12 overlaap in age N3. Depositional environment in the range of lowerbathyal zone bathyal-upper. Geological structures that develop in areas of research such as Kalinampu fault-shear, Mojosari reverse fault, Sumberan normal fault, Kalinampu shear fault, andthe Sumberan shear fault
