Can't identify strange bumpy fossil imprints

[Bob Clouser]

I found this chunk of tan siltstone recently at a roadcut along Rte 443/Rte 72 near Green Point, west of Swatara Gap, Pennsylvania. It's mapped as Devonian, Upper Mahantango formation. There are a lot of detrital bits in the rock -- bryozoans, etc. But the stuff I can't identify are the bumpy, wrinkled imprints. In some places the bumps seem to coat the inside of a tube. The bumps are 1/16th inch or less in size. At first I thought bryzoans, but there's no detail on the bumps, like living chambers. I think it's the external mold of some stalked animal -- corals, sponge, starfish arms?

 

Any help is appreciated!

 

Bob

[Rockwood]

Disarticulated bits of ... ?

[TqB]

Interesting - perhaps a calcareous alga along the lines of Mastopora/Cyclocrinites?