Fieldstone Foundations Question

[Andrew Brink]

Good morning BP Nation, 

I have a great opporunity to purchase a cashflowing duplex in an appreicating market however we were just informed that there are structural issues. Here is what the agent told us " There are some foundation issues. The hous is from the 1900s and it was built on old fieldstone foundation. Over the years that has shifted. It's not going to fall over however the foundation is not in great shape." 

The house is in great shape but the bones sounds questionable. 

Does anyone have experience with fieldstone foundations or dealt with a similar issue? What is the estimated cost to repair (NY)? Any tips will help! 

Thank you!