Printed from: https://conservationhandbooks.com/dry-stone-walling/know-your-stone/sources-of-stone-and-amounts-required/
In general, the best stone for use in walling is the local stone. Even if other stone can be obtained more cheaply, local stone preserves the continuity between the natural landscape, the older walls in the vicinity and the new work. Occasionally local stone is not to be preferred, if it is extremely fissile and...