I checked out a couple spots after work today.  No passage!  just filled with sand and rocks. not real impressive except for the size. 

 

links to pictures I took:

 

http://yophotos.fotopages.com/?entry=1490025&back=http://yophotos.fotopages.com/

 

http://yophotos.fotopages.com/?entry=1490058&back=http://yophotos.fotopages.com/