Spare Tire size in 1970 Dart?

Thanks, I have only had the Dart since the end of Feb and traded out the steele for a period correct Ralley, just want a spare for emergencies and fit in the well. OR I could always mount the spare as the 73 Challenger does over the axle under the window?
Menlo Park - Thanks I spent a couple years there at Menlo School of Business years ago. Small world. Thanks Dartpco70