JAGGAR: EROSION AND SEDIMENTATION. 305 
Tarr, R. $. 
The peneplain. Amer. Geol., 1898, vol. 21, p. 366. 
Williamson, W. C. 
On some undescribed tracks of invertebrate animals from the Yoredale 
rocks, and on some inorganic phenomena, produced on tidal shores, 
simulating plant-remains. Memoirs Manchester Lit. and Phil. Soe., 
1887, Ser. 3, vol. 10, p: 19-29, pls. 1-3. 
