First, contact your title insurer and raise the issue. Listen to what they say. There may not be a mistake but rather a different way of describing the same parcel.
If there clearly is a mistake, ask for a general endorsement correcting the description but don't stop there. Make sure all documents such as your deed and mortgage are correct.
It is entirely possible that the title insurer searched the wrong property and that's a problem. To protect your interests I always recommend that you review the title commitment PRIOR to closing. We like to give our customers copies of any maps or surveys found on record so they can look at the parcel and visually confirm we have searched the correct property.
Since we started sending the maps along with the title commitment prior to closing, we have eliminated doing at least two or three corrective deeds each year.
You might ask, well, how do these mistakes happen? Well, sometimes the sales agreement does not clearly identify the parcels being sold. This is especially an issue when the seller owns more than one parcel.
BTW- The danger of selecting the wrong property or creating a description error increases significantly if the title examiner has little or no experience. The risk of error goes through the roof when the lender or title agent relies on an automated search. Be picky and select a title company with expertise and one that assures you they are doing a FULL search performed by a human being and not a computer.