Here at work the imageshack link won't open.
But there was a Mammoth bicycle company in the early 90's headquartered in northern Cali somewhere, and they did indeed make mountain bikes. I think the models were M2000, M2200, etc... Not to be confused with the Raleighs of similar nomenclature (M200, M300, etc.). And also not to be confused with the old Panasonic MC (Mountain Cat, for those who are really curious) 2500, 3500, and so on.
My mistake, however, I was assuming the bike in the OP's post was one of these NorCal company bikes.
They were elevated chainstay with the downtube raised to pierce the seat tube, in a straght line with the chainstays. Very similar to the Brent Trimble carbon fiber bike.