Book excerpt: Mystery. Thrills. Adventure. Books 4 & 5 in the series: SKELETON SEA: A mystery at sea plunges forensic geologists Cassie Oldfield and Walter Shaws into deadly waters. When a boat is found deserted off the California coast, it looks to be a simple fishing accident. But there is nothing ordinary going on here. The geologists track the strange incident to an even stranger project. Someone with toxic skills is at work in this sea. RIVER RUN: There are plenty of ways to die in the Grand Canyon. The geologists investigate one way: Stranded raft. Life vests unused. Rafters missing. The only clue to the fate of the rafters is a bag of pebbles caught in the bowline. Following that clue, the geologists uncover a hellish scheme. Not only are the rafters in peril, but the river itself is under attack. -- All books in the series are complete novels, and can be enjoyed in any order. -- Book #1: Quicksilver -- Book #2: Badwater -- Book #3: Volcano Watch