The Savage model 24 was called an over and under.
Yes. It is an over and under, a combination gun, a rifle over shotgun, and a few other names for it.
http://www.guns.com/2013/03/20/savage-model-24-rfile-over-shotgun/My father's gun looks much like this one, though his is .22lr,/.410. If you look close, you can see the side release lever on the right of the reciever.
It seems, that a side by side rifle /shotgun would most likely be called a "Cape gun".
http://media.liveauctiongroup.net/i/31166/27014891_1.jpg?v=8D4899AAF04AA50They came in a wide array of models, including 30-30/12ga. (Iirc)
The have been reintroduced as the model 42 with synthetic stocks. (In .22lr/.410)
http://gunblast.com/images/Savage-42/DSC05371.JPGAnd Remington also has one with .410 /.22lr, but it looks goofy with the rifle barrel below the shotgun barrel (don't ask me why, it just looks wrong)
http://www.mrpolecat.com/articles/the_field_grade_combination_gun/index"....What is a "Field Grade" Combination Gun?
A combination gun is a firearm with two or more barrels of different calibers. Most are of a break action design, like a double-barreled shotgun. They almost always comprise a rifle caliber and a smoothbore shotgun caliber, but rare and oddball examples exist in multiple rifle or multiple shotgun calibers.
The vast majority of combination guns, both new and old, are of the two-barreled over/under variety, and are simply called "combination guns" or "combinations". The two most common configurations are a rimfire rifle barrel on top with a shotgun barrel beneath, or a shotgun barrel on top with a high-powered centerfire rifle barrel beneath.
Side-by-side variants exist, but are fairly rare. These are called "cape guns". They were most popular in the northeast USA, in previous centuries when black powder was still in common use.
Excessive variants exist, both new and old, mostly of German manufacture. Some have three barrels (called "drillings"), four barrels (called "vierlings"), or even five barrels (called "funflings"). Most drillings are comprised of two side-by-side shotgun barrels with a centerfire barrel beneath. Vierlings are usually like a drilling, but with a rimfire barrel added above. And funflings, well, they are just very rare and extremely weird, typically comprising side-by-side shotgun barrels, with centerfire rifle barrels above and below, and a rimfire barrel in the middle. These types of guns came about as a result of gun laws that allowed only one firearm per household, and for their utility in european driven hunts. I certainly wouldn’t want to carry such a gun on any sort of extended hike, though!"..."