Below are some pieces of a glass sponge called Hyndoceras bathense from the upper Devonian (Fransian stage) of New York. It comes from rocks that are part of the Chemung Group but I don't have more specific formation or layer info. Sponges are somewhat rare the find fossilized as they are composed of many tiny spicules that are held together by the fleshy parts of the body. When they die the fleshy parts decay and all the spicules get scattered. For the specimens below to have been preserved they must have been rapidly buried during a storm event or an underwater landslide.
The first two specimens are just one side of the sponge. Either the fossil split or was not preserved on the other side.
Specimen #3 is fully complete and 3-dimentional (except for being compressed by the sediments)
I purchased these specimens at my local Delaware Valley Fossil Society club show in April.
There is an impressive piece from West Virginia with multiple specimens that can be seen on the West Virginia Geological and Economic Survey page.