MTB Tire size?

I'm dusting off the old MTB & probably need to replace these weather cracked tires. Are MTB tires sized the same as road tires - in other words, a 26/19 tire would just be narrower than a 26/2.25 tire but both would fit on the rim?

I'm going to be doing more road/dirt road riding so I'd like to ditch the knobbies as much as possible. Any suggestions for tires? I always liked Continental for my road bike, but maybe MTB tires are different...?

TIA!

I hope you already have gotten tires by now, but if not, here's my take.

Road wheels and mtb wheels are sized differently. Road wheels are sized 700c x the width, from 19 (narrow) up to 35 (wider), maybe 38.

Mountain bike wheels are typically 26" (diameter) and the widths go from (typically) 1.25" to 2.5". For smoother surface riding, sounds like you should get some 26" by about 1.5 or so for both tires, with a smoother tread; make sure the front and back are the same. I'd ask your LBS what brand they recommend for the type of riding you'll be doing. If you like continentals, then by all means, get some for the MTB.

Have fun riding!