Sentence:  Old attitudes are held more tenaciously in the Tidewater than the Piedmont ; so that a line running down the length of the South marking the upper limits of tidewater would <WSD>roughly</WSD> divide the Old South from the new , but with , of course , important minority enclaves . 
Meaning of the word marked with <WSD> tags:  (of quantities) imprecise but fairly close to correct