XV Dinosaur Kingdom I AS02 - Puttering in the Palaeozoic (Revised Edition) by Redcode, Albbie

Once again, the X-VENTURE Xplorers find themselves in the past - 443.8 million years back, in the Silurian! Somehow, Rain managed to snare Emily in one of his schemes. However, they find far more than they bargained for when a group of prehistoric shellfish come, hungry for a bite-! Guess you have to expect that sort of thing while you're PUTTERING IN THE PALAEOZOIC!