The pattern calls for a 3 mm hook. This is somewhere between an American C and D hook. I would say you're right about it's being crochet cotton. A baby bootie pattern book I picked up recently uses crochet cotton. They use a size 7 or B hook. Not familiar with the crochet cotton. I mostly use yarn and larger hooks. Debating whether I really want to do this pattern or not. I'm getting older and the bifocals are getting weaker. Don't know if I'd be able to see the stitches. Thanks for your help.
Welsh corgis are cool.