LIMESTONE AND CLAY 39 



These are grouped under the general name of 

 Celtic pony. 



Limestone. Allowing for some districts, 

 like the central plain of Ireland, where the Ice- 

 sheet has left the country very badly drained, 

 a limestone formation usually makes dry soil. 

 The vegetable mould may hold a little water and 

 make mud, as on the chalk downs, but the 

 rock is so porous that most of the rain soaks 

 down, and the waters run mainly underground. 

 Moreover, the vegetable mould gives chemical 

 qualities to this water, which is enabled to 

 dissolve the rocks and form caverns on the 

 underground water courses. At the same 

 time the water becomes ' hard ' with lime in 

 solution, so that the springs will petrify moss 

 and twigs. 



The dryness of the ground tends to make 

 horses sound of bone. The carbonate of lime 

 in the water suppUes them with the material 

 for bone. As the result the bones are very 

 light in proportion to their strength. So this 

 pasture registers a well-built and very light 

 horse. If such an animal is of Bay blood, he 

 is larger and swifter than the Arab, lacking 

 only in soundness and in travel endurance. 



Clay. As clay holds water, its soils provide 

 abundance to the grass roots, and so produce 



