No. 1. VIEW LOOKING UP AT THE UNDERNEATH SIDE OF THE PROJECTING 
SHELF OF STRATIFIED ROCK WHICH PRESENTED THE CAST OF RIPPLE MARKS. 
The geologist’s hammer, tied to the end of a stick, was held against the ripple-marks 
to “ give the scale.” (See p. 61 ) 
Photographic 
Details : — 
Quarter-Plate 
Photographs. 
Lens : Zeiss Double 
Protar, Series 
VII a. Focal 
Length 5§ ins. 
No. i. Ordinary- 
Backed Plate. 
Speed 180 H. & 
D. Bright grey 
sky, no direct 
sunshine. 
Time: 9.30 a.m. 
S top f t 11. 
Exposure : 
3 seconds. 
Altitude : 
13,000 feet. 
No. 2. lsochromatic 
Backed Plate. 
Speed 220 H. & 
D. Clear grey 
light. 
Time : 1.30 p.m. 
Stop :// n. 
Exposure : 
\ second. 
Altitude : 
14,500 feet. 
No. 2. THE CESAR GLACIER, NORTHERN KEN IA. 
Side view from a distance of about half a mile. Photos by IV. M. Poss. 
