Digging a well, hitting a rock
You might want to check with knowledgeable people about drilling in your area.  Perhaps you have dug into bedrock.  Or there is a large monolith buried there. :-)


In the U.S., the USGS has much data available for your perusal.
Perhaps you have neighbors with wells?  Talk to them and see what their experience was.  Even if theirs were drilled 50+ years ago, well digging stories seem to survive the ages.
Your municipality might have well digging advice and experience and can advise on best drilling practices.