424 proceedijStgs of the geological society. [April 22, 



slates with thin grits, of Grafthole and Port Winkle, are succeeded by 

 the grey slates of Polscove, and these again by the grits of Sheviock 

 "VYood, which strike E.N.E. towards Creep; but they are poorly 

 represented, if at all, on the coast, and their place appears to be occu- 

 pied by the hard reddish arenaceous slates of St. Germans Beacon. 

 A. considerable belt of slate occupies the country to the north of 

 these grits, from Sconner to Polbathick and thence to St. Germans, 

 and runs out to seaward between Downderry and the Flag-staff 

 west of the mouth of the Seaton river, the dip being S. 20° E. at 

 Polbathick, and becoming south-easterly on the coast. Beneath 

 these slates are grit beds, which, striking down from Caracawn 

 Cross to the towns of Looe, overlie or include a band of limestone 

 north of the east town, and another at Hessen Eord. There is some 

 difficulty in correlating this latter with the limestone of Milladon 

 and St. Germans ; but the beds at South Bake dip westerly, and it 

 appears that some disturbing influence has been in operation in the 

 vicinity. 



If, however, we take the section up the Looe river a little further 

 to the west, we find the grit beds and limestone of the town of 

 Looe succeeded by a long downward succession of argillaceous slates, 

 which are occasionally calcareous, as in Common Wood, at the pools 

 opposite Trenant, at Terrors Pill, where we have the continuation 

 of the Polpever limestone, and at the bridge at the foot of the ascent 

 to Duloe. The section is not consecutive, and there are intervals, 

 where no rocks are exposed, wide enough for concealed reversals of 

 the dip to occur ; but we miss from the series the gritty bands and 

 reddish arenaceous slates so abundant between the base of the Hes- 

 singford limestone and the coast. Amid rocks, however, in which 

 grits appear so irregularly, this circumstance loses much of its 

 importance. 



If we follow the strike of the calcareous beds south of St. Ste- 

 phens by St. Germans to MiUadon, and thence to Tredinick and 

 Tremain, we have the northern limit of a group of beds which occu- 

 pies the interval between the volcanic rocks of Saltash and the 

 Plymouth limestone, deflected round to the south-east as we advance 

 towards the Looe river, by, as I beheve, the upheaval of lower 

 rocks between Duloe and St. Keyne ; and although, in the section 

 of the argillaceous rocks of the Looe river, folds and repetitions of 

 the beds may escape observation, there cannot be much ambig-uity 

 about the dip of the beds along the coast of Whitesand Bay, where 

 the bedding is rendered clear by the seams and bands of interstra- 

 tified grit. This belt of rocks, which on the Hamoaze occupies an 

 interval of no more than about two and a quarter miles when fol- 

 lowed to the Looe river, widens out to nearly three times that dis- 

 tance. This appears to be due partly to the lowering of the angle 

 of dip, and partly to the addition of arenaceous materials which have 

 come in from the south-west or south ; at the same time there is the 

 possibility of some concealed repetition of the beds between the 

 Lyhner river and the coast. 



The attempt to determine the relations of this belt of rocks west- 



