Because you asked for info: Your button is indeed an EXTREMELY rare Confederate Army Engineer Officer button. Yours manufactured by the button-making firm of William H. Dowler in Birmingham England, sometime between 1861 and 1865. It was run through the yankee navy's blockade of Southern seaports... and because you dug it in North Carolina, it provide arrived there on a blockade-runner at Wilmington NC. A caution-note for diggers & collectors: I should mention, it's very important that yours has the exactly-correct form of W. Dowler backmark ("W. Dowler Superior Quality") for being from the civil war time-period. In 1903, the Dowler company manufactured a number of what are called "restrikes" of their civil war Confederate buttons, using the very same stamping dies they used for making the civil war ones. But by 1903 the company's name had changed to "Wm. Dowler & Sons Ltd. - Birmingham." So, if a Dowler button's backmark says "Sons" or "Birmingham" it is from several decades after the civil war ended. You say you dug it at an old house-site in NC... so I recommend researching old County maps and tax-records to find the name of the owner of that house from 1850 to 1900. Perhaps he served in the Confederate Army as an Engineer Officer.