Hill's 1881 History of Coshocton County, page 481 in context of early settlers of Clark Township:
"Isaac Purdy, from Pennsylvania, settled upon lot 11, section 2, prior to 1822."
Ibid.page 484 in discussion of the village of Bloomfield, now Clark:
"The first buildings in this vicinity were the cabins of the Craigs, built over sixty years ago; then one was built in Holmes county by Aaron Purdy. James Kerr, about 1835, erected a cabin on the spot now occupied by Doak's new storehouse. The first store was opened across the line about 1842, by Aaron Purdy, and afterwards kept by James Kerr. But it did not remain in operation long. Teachout & Towsley started the first store on this side about 1845, in James Kerr's house. Charles Poe, about 1846, built a house where Doak's old building stands, and commenced mercantile business there. He died soon after, and Patrick Foley, Robert Graham and the present merchant, have successively operated here in this line since. After Purdy and Kerr ceased merchandising on the Holmes county side, John Fisher kept a tavern in the building, for awhile. The first tavern had been opened years before, by William Edgar. O. Williams is the present hotel proprietor of the village, the hotel being in Holmes county"
Ibid, page 557 in discusion of settlement of adjacent Mill Creek Township:
"Other settlers who were in the township about or before 1820, were Daniel Weaver, who settled upon the northeast quarter of section 3; John Stonehocker, the northwest quarter of section 19 (he died on the place several years later); Amos Purdy, a New Englander, who afterward moved, farther west, the northwest quarter of section 13;"
I haven't run across the McDarmant surname.You may want to check our McDermott and McCammant, both of which appear in Coshocton County records.