"England Births and Christenings, 1538-1975," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:NPWR-FHB : 11 February 2018, Josiah Seymour in entry for Priscilla Seymour, 25 Jun 1801); citing , index based upon data collected by the Genealogical Society of Utah, Salt Lake City; FHL microfilm 0590699 (RG4 121), 0590699 (RG4 1229), 0590699 (RG4 2270), 0590699 (RG4 2271).
It may be possible to confirm family relationships with Josiah by comparing test results with other carriers of his Y-chromosome or his mother's mitochondrial DNA.
Y-chromosome DNA test-takers in his direct paternal line on WikiTree:
Denny Seymour :
Family Tree DNA Y-DNA Test 111 markers, haplogroup R-BY3298, FTDNA kit #108347 +
Y-Chromosome Test 419 markers, haplogroup R-Y20344