Sentence:  And farther, that being fitted to each other on their flat sides, alternate male and female (see drawing annexed), by means of the <WSD>shoulderings</WSD> or wedgewise-securings, and abutments, which will be better and more clearly understood by a view of the drawings annexed to these presents, and to which we hereafter particularly refer; 
Meaning of the word marked with <WSD> tags:  A flanged portion of something, similar to a lip but occurring on the side rather than the rim.