MAPPING. 27 



In making another expedition to survey the fourth 

 slip, fig. 8, we enter upon its area, let us suppose, near 

 the top of the chalk escarpment, which is completely 

 overlooked from the road. We pass on by the windmill, 

 not troubling to search for sections as chalk everywhere 

 abounds, turn to the left at the branch roads, and 

 presently observe in a road cutting some mottled loam, 

 yellow, red, and brown. In slip 3 we found grey sand 

 apparently resting on the chalk this is something very 

 different, and we dig a trench down the side of the 

 cutting to ascertain if the grey sand be here beneath 

 the loam. It is not, but we come upon a bed of dark 

 brown clay enclosing green-coated flint pebbles, and below 

 this the chalk itself. We make our notes of these facts 

 (Part II.), find our exact position on the road by a 

 bearing (N.) on the windmill, and draw a line across the 

 road at the boundary. Nothing more worthy of note 

 occurs until we come to a small pit near the corner of 

 the map, dug into clean grey sand similar to that in 

 slip 3. This is put down* on the map by aid of a bear- 

 ing (N.E.) on the farmhouse and pacing the distance 

 therefrom, as no other object is visible on which to take 

 a second line of bearing. 



On the other road in the slip is a brick-yard, where 

 the junction of the chalk and overlying mottled loam, 

 including the brown clay with green pebbles, is visible 

 and we ascertain that sand occurs just to the S. of 

 this spot. From this we conclude that the sand here 

 rests on the loam, and getting occasional hints from the 

 drains and ditches, we draw our lines, and the mapping 

 of slip 4 is completed. 



The four slips which we have surveyed form parts of 



