Let's see, he was 74 and she was 62. I'd guess either an accident (overturned buggy or something), or an illness they both caught. I notice the three links at the top of the stone, so he was an Odd Fellow. You might find that the Grand Lodge of Arkansas has something. It might also be worth checking Russelville newspaper records to see if there was an epidemic in town at the time. Winter, might have been flu...