This is an interesting piece of matrix from the Centerfield member of the Ludlowville formation that I found near East Bethany, NY. It has a rugose coral, likely Heliophyllum, that colonized a fallen branch of Favosites sp.
A closer view of the Favosites and you can see an eye and partial cephalon of a Phacops on the left side of the picture.
You can clearly see that the horn coral originates in one of the vacant cells on the branch of the Favosites. I like all the twists and turns that the calice of the Heliophyllum takes as it grew.
The Centerfield member of the Ludlowville formation represents a period of lower sedimentation, and possibly higher sea levels, which allowed the coral fauna to prosper. It corresponds to the Hungry Hollow member of the Widder formation in Canada and has been correlated to a section of the Mahantango formation, in Pennsylvania, called the Centerfield coral reef.