What type of fossil is this found at northern Ohio? I need some help identifying this fossil.  


I found the rock 30 years ago along the Cuyahoga River in northern Ohio.
Northern Ohio is glaciated so it is possible that the specimen was transported to Ohio. 
The rock is approx 1.5 x 2.5 inches (3.8 cm x 6.3 cm).  
The rock is calcareous reacting to HCL. 
The rock feels the correct weight for its size.
Of course 5 minutes after I post the question, I find the answer myself:
Halysites (Chain Coral) fossil extinct coral from the Silurian period.