The Ipbong Andesite is a stratigraphic unit which is lain in the lowermost part of the Yucheon Group in the southeastern Yeongyang sbbasin. The Ipbong Andesite is lain on the Sinyangdong Formation and under the dacitic tuff, and consists in its lower andesitic tuffs and upper lavas. The andesitic lavas show some alignments of elongate vesicles filling with calcite amygdules and plagioclase microphenocrysts, and show rare imbrication of the microphenocrysts in vertical sections parallel to them. The flow directions which is measured from the flow indicators are laid along NNW-SSE trend in the eastern part and NNESSW in the southwestern part of the study area. Movement pattern from the flow lineations suggests that the Ipbong Andesite had a fanlike pattern by flowing southwards from the mid-northern part. Accordingly a small diorite stock in the mid-northern part area may probably be a source area of the Ipbong Andesite.