26. Iron—2.3g to 3g
[% by mass of the more common elements in the average human body]
Ordnance Survey Office,
April 9th 1830
An uniform System of Indicoclature is expedient in the Geological Plans and Sections connected with the Ordnance Survey; and I therefore direct your attention to the following Table of Letters and Colors by which the Rocks and Strata of most ordinary occurrence will be expressed.
I am, Sir,
Your very obedient Servant,
Lieutenant-Colonel Royal Engineers,
[Source: http://www.largeimages.bgs.ac.uk/iip/mapsportal.html?id=1003599 | Made available under the Open Government Licence | Contains British Geological Survey materials © NERC 2015]
For instance, on Horse Head Moor above Upper Wharfedale the stone walls are riddled with (intentional) holes. The gaps protect the walls from wind damage yet contain the herd animals. These divides cry out to be breached, for us polite ramblers this may be via a stile or kissing-gate, for the fell runner it may be with a hearty leap (of faith). And what of the traditional laid hedge? Again, the stock is contained yet the weather permeates the divide, as do the more agile creatures of the field. The rambler, fearing the quickthorn, wisely seeks the gate though.
Of course, these boundaries aren’t just scaled-up versions of the black line on the map either. They are environments in themselves: places to look out from, to nest in, to feed from and it is only the perception of the herd animal that sees them as containers.