The tombstone of John Clark was listed in the 1981 publication of "Montgomery County Texas Cemeteries, Vol. IV" on page 5. This survey of Danville Cemetery was taken on 28 April 1978 by Oveta and Horace Wright. At the time of that writing, the inscription on his broken stone gave his death date as 21 Oct. 1879. There is no evidence of the stone left at this writing (2007). It may have sunk or was removed by vandals.

John Clark is found on the 1870 Danville, Montgomery Co., TX census, p. 4. He is a white male, 37 years of age, living alone and his occupation is as a Merchant. He gives the value of his Real Estate as $400 and the value of his personal property as $6000. His birthplace is listed as Ireland.