adj.分角的(略带棱角的；半多角形；半多角形砂)
The middle oil-member is characterized by medium-sized sandstone and pebbled sandstone, with fair sorting and subangular sphaericity.Rock types mainly were feldspar debris sandstone. 中油组主要沉积中砂岩和含砾中砂岩，粒度整体较粗，分选性较好，磨圆度以次棱角状为主，岩石类型为长石岩屑砂岩。
