From scrub + stone. <span class="searchmatch">scrubstone</span> (uncountable) (archaic, UK, dialect) A form of calciferous sandstone. “<span class="searchmatch">scrubstone</span>”, in Webster’s Revised Unabridged Dictionary...
curbstones plural of curbstone <span class="searchmatch">scrubstone</span>, subnectors...
subnectors plural of subnector curbstones, <span class="searchmatch">scrubstone</span>...