140 APPENDIX I 



Strathdon and Strathdee contain an assortment of nearly all the above-named formations 

 with a few others in parts. The Forfarshire and Central Perthshire moors lie principally 

 on quartzite and mica schist. Ayr, Strathclyde, and the Lothians contain a large assort- 

 ment of different carboniferous rocks, while in the Southern Highlands from Wigtown 

 on the west to Berwick on the east the most representative formations are graptolite 

 shale, Llandovery, old red sandstone, Ludlow, and Wenlock. 



With regard to meteorological conditions the case is different, as may be seen at a glance 

 from the Rainfall Map of Scotland published by Messrs Bartholomew for the Journal of 

 the Scottish Meteorological Society for the years 18G6 to 1890, and here reproduced by the 

 kind permission of Messrs Bartholomew and of the Society. It will be seen that the 

 principal Grouse-producing areas coincide almost exactly with the districts of low and 

 moderate rainfall, the only exceptions being in the western districts of Sutherland and 

 Ross and the islands of the Outer Hebrides. Whether the heavy rainfall has a directly 

 detrimental effect upon the Grouse, or merely affects it indirectly by preventing the best 

 development of the heather on which it feeds, may be a matter of conjecture, though the 

 latter seems the most probable explanation. The fact remains that where the rainfall is 

 heavy Grouse are few, and it is feared that this fact will always prevent the Grouse moors 

 in certain rainy districts from being brought to the same standard of productiveness as in 

 more favoured regions. 



The points brought out by the series of maps may be summarised as follows : 



(1) " Grouse Disease " is one of the natural risks to which Grouse are subject, and is 



to be found wherever Grouse are numerous. 



(2) Except in specially favourable seasons there is always a certain amount of " Grouse 



Disease" in one district or another. 



(3) " Grouse Disease " does not usually persist in the same locality for more than one, 



or two years. This is probably due to the fact that by the reduction of 

 the stock the risk of further attack is lessened. 



(4) There is no connection between " Grouse Disease " and the geological formation 



of the district in which it occurs. 



(5) Where the rainfall is heavy there are few Grouse and 

 Where the rainfall is heavy there is little " Grouse Disease." 



