The OP said its called Jeffrey Stone and it's off of MacArthur in North Little Rock. Jeffrey Stone, according to the Internet, was an old quartz mine. From what I read it is supposed to be closed (also due to drownings) but there are several access points into it so it is still accessible.
I haven't actually been there yet but I have looked for it on Google maps and have not been able to find it. The OP says he was headed towards Morgan and took a right turn off of MacArthur.