Silver object seen hovering over marsh in West Dennis during daytime on 9-11-12On Tues., 9-11-12, at 1:30pm, I was taking my daily walk in the West Dennis Beach ( Cape Cod, MA ) parking lot. To the left of the lot is the south facing Atlantic ocean and to my right is Bass River and salt marshes where many will canoe, where Giant Blue Herons feed and Osprey's nest. It's not unusual to see birds that are quite large flying over the marshes.On this particular day, the Mystic Seaport Aquarium was releasing a young seal that it had rehabbed after an injury into the Atlantic on my left. At least 50 people were there watching this, so all of their attention was focused onto the left hand side of the lot on the beach.I walked past and noticed to my right, over the marsh, a very odd shaped, large object that I naturally assumed was a bird. It seemed to be just suspended up there, very slowly moving. The size was approx. the size of a dime held in my fingers with my arm extended at a 75 degree angle.Once I started to pay attention to it, I noticed that as it slowly moved, it reflected sunlight and appeared silver with a shape that made me positive it wasn't a bird. I have since looked up online for the shape and the exact match to what I saw was the 1947 Kenneth Arnold craft sighting.At this time I saw that it started to speed up, so I was struggling to get my cell phone out of my pocket to take a picture, but it streaked out of sight in a flash before I could even turn it on. I was the only one watching this because all others were watching the seal release.