Actually, Luccio states in Small Favor that one runs directly under the Field Museum; it didn't pool there at all. Harry was able to use the energy of the Ley Line to reanimate Sue, and that was is the middle of a huge ongoing ritual (i.e. the Darkhallow) and on Halloween night; I don't think he could have done it otherwise.
Harry even says so himself. It took a guy of harry's level of mojo, plus the darkhallow, plus the ley line, plus a tutoring session in kemmlerian necromancy from a fallen angel and a nearly complete skeleton (only missing the skull cause it was busted) to pull off.
As harry says "it wasn't complicated... Lifting an engine block isn't complicated. " It just took ALOT of juice.
Dinosaurs might be a stretch without the ley line and the darkhallow breaking the barrier. Fossilized wolves or sabretooth tigers though? Game on with some uber prep