26 ILLUSTRATIONS 



Plate 

 No. Page 



56. Sand rippled by two sets of waves, which were probably 



simultaneous ; at Grange, Lanes . . . .271 



57. Sub-aqueous sand-waves moving up-stream and carrying 



with them their superposed water waves ; at Cannes . 275 



58. Current-mark made during rain by a temporary stream on a 



sandy road, photographed after the road had dried . 283 



59. Current-mark on the sands of the Dovey estuary, with larger 



sand-waves which have been flattened as the tidal water 



ran off ...... . 287 



60. Tidal sand-waves, winding channels of ebbing tide, and 



shining mud patches in places, where horizontal eddy- 

 ing probably occurs. Mawdach estuary . , 293 



61. Tidal sand-waves in the estuary of the South Esk, Montrose 297 



62. The river Severn between Beachley Point and Severn Tunnel, 



showing the Dun Sands ..... 301 



63. Two sets of tidal sand-waves caused by successive currents 



in different directions, on the Dun Sands, river Severn . 304 



64. Tidal sand-waves and current-mark ; Dun Sands, river Severn 307 



65. Map of the estuary of the river Dovey . . • 311 



66. Tidal sand- waves of which the daily movement was measured ; 



Dovey estuary {top) . . . . '314 



Tidal sand-waves with current-mark in troughs ; Dovey 



estuary {bottom) . . . . . -314 



67. Tidal sand- waves and low-water channels ; Dovey estuary . 317 



68. Winding channels of the ebbing tide ; Dovey estuary , 320 



69. Tidal sand- waves, at right angles to the sea shore, in a "low," 



or depression ; at Mundesley {top) . . . 327 



Tidal sand-waves partially obliterated on the sea shore ; at 



Mundesley {bottom) ..... 327 



70. Tidal sand-waves on the North Goodwin . . . 330 



71. Pools formed in the trough of a tidal sand- wave by the 



washing-off of crests during ebb-tide ; at Montrose . 333 



72. A fan-shaped deposit of sand, showing a stream of water 



which soaks into the porous material ; at the foot of the 

 East cliff, Bournemouth . . . . -341 



73. Tongues of sand, each of which is instantaneously formed 



by the sudden subsidence of the water by which the 

 sand grains were carried ; at Bournemouth . . 344 



