"United States Census (Slave Schedule), 1850 ", database with images, FamilySearch (http://www.familysearch.org/ark:/61903/1:1:HRWN-Z5N2 : 20 September 2020), Jos B Clarke in entry for MM9.1.1/MVCQ-MJ1:, 1850.
Transcription from line 10, right side: Jos A Clark, number of slaves 1, age 13, Male, Black
Series II. Clark Family Papers 1751; 1773-1781; 1841-1969; and undated, Box: 36. Joseph Lynn Clark Papers, MS 156. Archives and Special Collections, Mary Couts Burnett Library. http://archives.16300a.com/repositories/2/archival_objects/12157
Transcription: On or before the first day of January next I promise to pay J. A. Clark, or [indecipherable] one hundred & fifty dollars, for the hire of his negro boy George, from the first of February, 1856 till the first of January 1857. And I further promise to furnish said boy with two good suits of clothes and two good bed blankets and pay the tax on him for the present year. Feb 1, 1856. (Note signature on bottom right.)
"United States Census, 1860", database with images, FamilySearch (http://www.familysearch.org/ark:/61903/1:1:MXFX-HBY : 11 November 2020), Joseph Clark, 1860.
Transcription, starting on line 1: Jos A Clark, age 40 (incorrect), Male, Stock Raiser, born in Illinois; Hetty, age 36, Female, born in Alabama; Addison, age 18, Male, born in Texas; Randolph, age 15, Male, born in Texas; Ida, age 10, Female, born in Texas, Thomas, age 4, Male, born in Texas, age 2, female, born in Texas, Rachel DeSpain (Hetty’s mother), age 75, born in Kentucky, John Walles, age 21, Male, Stock Herder, born in Tennessee.
"Texas, County Tax Rolls, 1837-1910, Collin County", database with images, FamilySearch (http://www.familysearch.org/ark:/61903/1:1:QJ8G-TF4D : 19 November 2020), J A Clark, 1860.
Transcription from line 5: Clark, Joseph A. owned 160 acres valued at $1200, one negro, valued at $1000, 4 horses, valued at $300, 600 sheep valued at $1800, for a total of $4300.
"Texas, County Tax Rolls, 1837-1910," database with images, FamilySearch (http://familysearch.org/ark:/61903/3:1:939F-W8XC-Q?cc=1827575&wc=M636-WPD%3A161580501%2C161401001 : 22 May 2014), Hill county > 1864 > image 1 of 23; State Archives, Austin.