The cowl is Purl Soho's Bandana Cowl, which originally calls for super-bulky weight yarn on 10 1/2 needles, but Silas' is worked up from Lion Brand Wool-Ease (worsted) on size 6 needles. It follows the pattern to the letter, except that for the decreases after the short rows, I worked only 3 over the 24 rows instead of 6. The result fits perfectly, and looks pretty dashing to my eye. Of course, mine is the eye of the person who made not only the cowl but also the adorable child (with help), so it may not be the most neutral information source.
There is a hat that goes with that jacket, incidently.