n.[古生]牙形刺；牙形石
The Silurian strata containing abundant conodont fossils are well developed and comformable with the overlying Devonian strata in the Baizitian region, northern Yanbian, Sichuan. 四川省鹽邊縣北部稗子田地區(qū)的志留系發(fā)育良好，牙形刺化石極為豐富，與上覆泥盆系連續(xù)沉積，并呈整合接觸。
