Thank you for your reply. I have the following on Wm. Markle:
Sgt. William Markle (1783-1813)
He was the son of Henry Markle and Mary Vrooman, of New York, and was probably born in the Niagara region (Mar1). A Wm. Markle owned land in the Dundas Valley in Ancaster Twp. (TD pg. 12). A Sgt. Wm. Markle served in Capt. James Durand’s 2nd Flank Co. of the 5th Lincoln Militia when it was established in 1812 but died in January, 1813 (D237)(W4B). The 2nd York and 5th Lincoln Militia Regiments sometimes formed combined detachments.
You can find most of my transcript at http://www.ogs.on.ca/services/1812-militia.php
where you can see who Wm. was serving with. You will also find my email address there. If you email me directly I will send you my other sources and will be able to contact you if I learn more about this family. Please let me know if Wm. was married.