Sagada Sumaging Cave has Seashells Imprints

I found this recent, very clear photo of Sagada shell fossils in Sumaging Cave at the TrekNature galleries. I've seen these imprints while I was in the cave more than a decade ago. It's supposed to be proof that Sagada, with its vast network of limestone caves was once underwater many thousands or millions of years ago. I'm not sure if they're fossils though - or they're actual shells. This particular picture is amazing in clarity because the ones pointed to me before were high up in a wall, and with only the Petromax light, I couldn't see the imprints very clearly. Visit this TrekNature gallery for a higher resolution view of the image.