Dinosaur-like humanoids developed advanced technological capabilities

An enigma with which I dealt extensively in Worlds Before Our Own has to do with what appear to be humanoid footprints which are found widely scattered in the geologic strata suggestive of a quarter of a billion years ago. This "What's-it That Walked Like a Human" left shoe prints, sandal prints, and barefoot prints on sands of time that have long since hardened into rock.