THE PROGRESS OF SCIFNCF. 



383 



Mr. E. J. Garwood thus describes 

 the Whin Sill, Hugh Force, Teesdalc: 

 This is a classical waterfall, described 

 by Sedgwick in 1823, Wm. Button in 

 L831 and Phillips in L836. The fall 

 is 70 feet high, over the Whin Sill, 

 which is here intrusive in the Lower 

 Yoredale Beds. The photograph shows 

 the chief fall near the right bank of 

 tin' Tecs. It is working along a joint 

 in the hard Whin which forms the pro- 



the latter is of the normal type de- 

 scribed by Teall. 



Mi. \\ '. A. E. Ussher gives an ac- 

 count of the natural arch at Torquay: 

 The natural arch depicted in the photo- 

 graph forms a conspicuous object on 

 the south coast of the Torquay Pro- 

 montory between the Bath Saloons and 

 Daddy Hole. It has been tunneled 

 by the sea through a small headland 

 near the axis of an inverted synclinal 



SHf\ v 2?3S'. 



Natural Arch at Torquay. 



tective cap to the fall; when in flood 

 surplus water also pours through a 

 second joint near the left bank. The 

 undercutting of the limestone is shown 

 by the caves and the hanging icicles; 

 the gorge below bears testimony to the 

 recession of the falls. The section is 

 as follows: Whin sill, 30 feet; shale, 

 thinning out, 2 feet; whin, 9 feet; 

 shale, altered, with superinduced pris- 

 matic jointing, 15 feet; hard limestone, 

 with pyrites, 8 feet; hard, fossiliferous, 

 crinoidal limestone, 20 feet; coralline 

 limestone, 6 feet. The limestone is 

 altered and saccharoidal to a distance 

 of 35 feet below the base of the whin; 



curve in Middle Devonian Limestones. 

 The prolongation of this axis eastward 

 is well shown on the coast a quarter of 

 a mile away. In the middle and lower 

 part of the limestone masses of Tor- 

 quay, a partial cleavage is often dis- 

 played by the beds, consequent on the 

 pressure which has produced the fold- 

 ing in them; this structure, as shown 

 in the photograpb, becomes in certain 

 cases most pronounced at and near the 

 axis of the folds, causing a shattering 

 of the rock at the point where the direc- 

 tion of strain cleavage approximates to, 

 or coincides with, the inverted bedding 

 I planes. The dark marking extending 



