This is the 2nd edition of the 5th book in a series of roadside geology books. Here we explore the Precambrian geology along Trans-Canada 17 from east of Thessalon to east of Sudbury, Ontario. This guidebook is in full color with 19 pages of relevant geologic information, to include charts and diagrams. Plus there are 19 individual studied outcrops that you can visit. The guidebook gives GPS coordinates for all stops, so you can explore them in any order. We explore the Huronian Supergroup meta-sediments and the later igneous intrusions. We begin near the north shore of Lake Huron then head east and swing around the southern side of the Sudbury impact crater into the Grenville Province. All the stops are on public land, plus Chutes Provincial Park. This book includes one more stop than the first edition, along with a couple of updated diagrams and figures.