Flat felt roof hot laid.
Correct me if I'm wrong but the grano chips are added to create a heat barrier to prevent the felt blistering in hot sunny days (UK its a joke its peaing down) and as grano chips are expensive for a small bag can pea shingle be used in stead with same results.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix roofing.