the LBS threw away this Schwinn High Sierra Mt. Bike . It had good components and only lacked a handlebar and some TLC.But the stem is unlike any I have ever seen. Maybe since I have been away from cycling for a while (30 years ago I was hit by an 18 wheeler, and that took me off the road for a while) Anyway the stem looks like a wishbone, and attaches to the bars at two spots, the angle is intense so my bars are really up there , (good for me since I am much older- 70 years old on 2-7-2010) Can anyone explain what I have here? btw I attached teal mustache bar from a thrown away girls bike and my water bottle is also teal,,,The bike is coffee colored. It has a cro mo frame and Shimano Deore components. It rides really well.

Are you describing something like this?

I used to see stems like this on the odd bike from the 80's at the co-op. I think they did show up more often on Schwinn bikes. BMX bikes sometimes had something like it, a much stubbier version, but still a quill with two seperate clamps on it.

I'm not really sure what to make of them other than that.

I try to ride a little each day and have several fairlry flat spots to ride on. one is c9 to rs Cloud nine to the rest stop u are anywhere near Hot Springs Ar and want a riding partner consider me,I am slow and wont run off on you ,70 east 2 mile loop on the shoulder of the hiway. Hittin the Wal- (mart) on Central the perimeter of wal-mat with parking lot and loading area is .6 mile and flat, and the Whit -Lap around Whiitington parks loop all of these little rides of mine are flat but can include a good climb that is attached. I even have spare bikes if you are bikeless for any reason

exactly. you are a great help

This was an attempt to stiffen handlebars before larger headtubes/steerer tubes/headsets.

That stem is old. It's from the late 1980's.

I worked in a Bike Shop for a while before I joined the Navy. Seen plenty of them.

As others have said, those were common in the '80s. I had one on my first mountain bike, a Mongoose I got in '83 or '84. They work fine; if it's in good shape there's no reason to worry about it.
One thing to watch if you do replace: a lot of those, including mine, were an old-school diameter, I think .833 inch, that had been the American standard on kids' bikes and cruisers. The industry was just starting the move to what were called "one-inch stems" (actually 22.2mm, while an inch is 25.4mm. And just to complicate things, French bikes' stems were 22.0, just enough difference to they didn't interchange with either of the others). One-inch stems are still fairly easy to find, but if you have one of the .833s, good luck...

22.2mm is the inside measurement of the steerer tube, 25.4mm is the outside measurement.

25.4 OD 22.2 ID gives 1/16" wall thickness. Tubing sizes were standardized on their ID, so that is normal 7/8" tubing.

those stems came on early MTBs, it came stock on a 1984 Mongoose MTB I own and I've seen them on a few other bikes from the era, probably originated on BMX bikes