Yes, there is a Stephen H Clark buried in the Sarona Cemetery. The stone says he was born in 1836 and died in 1914. He served in Co D, 28th WI Inf.
Also buried in this cemetery (Sarona) is a Sarah E Clark. She was born in 1853 and died in 1937.
There are several Clarks (Francis H [1836 - 1915] and Lewis E [1829 - 1914]) buried in the Madge Cemetery which isn't too far away from Sarona, just in case you're interested.