Identifying features of a mountain bike specific to a tall and heavy rider? I recently found some local bike trails that have everything from flat gravel to dirt bike jumps. I'm looking for a bike that can hold me through off road biking. I don't plan on doing any jumps or anything, but definitely offroad trails.

I've looked around a bunch and haven't been able to find many bikes that have an actual weight limit listed.

I'm hoping to find something around the middle of the price range, but I know most things for heavy guys tend to be a lot more expensive. 

I am brand new to biking so any and all tips are very much appreciated!  I'm 6'3" (~190cm) and 325lbs (~147kg).
I would be looking at bikes with frames made of steel. A cro-moly frame will be most likely to meet the requirements you are looking for on your budget, and there are a lot of bikes with cro-moly frames available in different price ranges. Companies like Trek and Diamond Back make high quality bikes in every price range, you would just have to look at how each bike specs out for weight limits. Dont rule out alloy bikes, I just think they tend to fatigue faster under rigorous use. There is a company called Zize Bikes that might interest you, although they look pricey.