SIXTH REPORT OF THE DIRECTOR I909 163 



is shown in plate 4. This wall still retains for the greater part 

 its former glaciated surface. The whitish horizontal band, due to 

 the dried remains of a sheet of green algae which covered this 

 portion of the wall in the spring, is an indication of the water level 

 at that time. It may be noted that the portion of this wall covered 

 by water the greater part of the year is better preserved than either 

 the portion only covered in spring or the portion above this which 

 is now never covered.- The water surface shown in this plate cuts 

 across the mouths of several small wedge-shaped caves or cavelets 

 and their appearance is very suggestive of glaciation after their 

 formation. The clean and sharp junction with the smooth curved 

 glaciated wall makes them appear like the younger ends or remnants 

 of older and larger joint caves. The fact that a very marked and 

 glaciated notch has been cut out from the under portion of the cliff 

 just north of them and at their level, may be taken as indicating 

 that a few closely packed joint caves had here so weakened the 

 cliff* as to allow glacial action to carry them in part away. Their 

 former presence is shown by their bases which still exist. The 

 well preserved character of this portion of the wall is due to the 

 proximity of Valcour island on the west, to a bar at the north (here 

 indicated by the faint lines of surf), and to the fact that waves 

 from the south are broken by cliffs as they enter the channel. 



There are a few instances in which these cav^es have followed 

 bedding planes, and cut such wide and deeply penetrating caverns 

 as to bring down great masses of the rock above. Plate 10 repre- 

 sents a portion of the shore of Valcour island as seen from the 

 south end of Spoon island October 23, 1909. The great fall of 

 rock at the left end of the cliff is due to the collapse of such a 

 cavern. A little to the right of the middle of this view there arises 

 from under the water a second low but wide cavern which follows 

 the bedding plane seen at the right. The vertical dimensions of 

 this cavern become rapidly less as we move up along the bedding 

 plane and they become practically zero before we reach the highest 

 part of the dried algae belt, plainly seen as a whitish band parallel 

 with the water surface. The width is considerably greater than 

 here shown because it extends to the left under water. The distance 

 to which it penetrates the cliff horizontally was greater than could 

 be determined. The wall here is a north and south fault scarp, is 

 on the upthrow side and is but a few meters from the fault line 

 itself. Not far back of this we find a few parallel faults with very 

 small vertical displacement, but revealing, by slickensided surfaces, 

 a larger horizontal component. The cliff to the right of the portion 



