In an article in our local newspaper, there was a distinction made between the American wooly mammoth and the mastodon. In a nutshell, very mature mammoth males had tusks that grew gradually toward one another and eventually into a crisscross. Not so for the mastodons. Also, mastodons, not relatives of current day elephants as in the case of mammoths, had rounded rather than flat molars; mammoths had flat-topped molars.