CHAPTER XI 
WILD-GEESE ON THE SAND-HILLS 
FLANKING the marisma and separating it from the dry lands of 
Dofiana, there rises rampart-like a swelling range of dunes—the 
biggest thing in the sand line we have seen on earth. For 
miles extend these mountains of sand, unbroken by vestige of 
vegetation or any object to relieve one’s eyesight, dazzled—aye, 
blinded—by that brilliantly scintillating surface, set off in vivid 
contrast by the azure vault above. 
Should a stranger, on first seeing those buttressed dunes, 
be seriously informed that their naked summits constitute a 
favourite resort of wild-geese, he might reasonably suspect his 
informant’s sanity, or at least wonder whether his own credulity 
were not being tested. Yet such is the fact—one of the surprises 
that befall in Spain, the pays de Pimprévu. 
The paradox is explained by the stated necessity in wild- 
geese to furnish their gizzards with store of grit or sand for 
digestive purposes. 
This supply, so long as the marisma is dry, they are able 
to obtain from those raised ridges of calcareous debris (already 
described, and known locally as vetas) which here and there 
outcrop from the alluvial wastes. But when winter rains and 
floods have submerged the whole region and thus deprived the 
fowl of that local resource, they are forced to rely upon the 
sand-dunes aforesaid and to substitute pure sea-sand for their 
former specific of calcareous grit or disintegrated shells. To 
the sand-dunes, therefore, in the cold bright mornings between 
October and February, the skeins of greylag geese may be seen 
directing their course in successive files, in order, as the Spanish 
put it, “to sand themselves” (arendrse). 
A notable fact (and one favourable to the fowler) is that, 
though these dunes extend for miles, yet the geese select 
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