CONTENTS 19 



CHAPTER IV 



PAGE 



SNOW-MUSHROOMS AND CAHOTS . . . .211 



Snow-Mushrooms. 



Weather and snowfall in the Selkirk mountains, B.C. 

 — Snowcaps on high stumps of felled tree sat Glacier 

 House resemble large mushrooms — Diameter, 9 feet 

 — Weight about i ton — Shape due to bending under 

 its own weight — Mode of growth — Reason of their per- 

 manence. 



On the Sparseness of the Falling Snowflakes. 



Cahots, French name for undulations made by sledges 

 in snow — Formed on the ice of the St. Lawrence — In 

 the streets of Montreal — None in Manitoba during 

 midwinter — Similar undulations on an ordinary rough 

 road at Coniston, Lancashire, produced by a sledge. 

 Experiments with a small model sledge — The undula- 

 tions are produced without an initial inequality — And 

 during slow and steady motion — They are due to a 

 loose but adhesive condition of the road — Other 

 examples of transverse inequalities of roads. 



PART III 



SUB-AQUEOUS SAND-WAVES 



CHAPTER V 

 RIPPLE-MARK AND CURRENT-MARK .... 257 



Ripple-mark. 



Sir G. H. Darwin's experimental reproduction of ripple- 

 marks — My measurements of natural ripple- mark — 

 Osborne Reynolds' experiments. 



2 



