The only birth record found on familysearch.org within 20 years of 1775 is for George Messerly is George Messerli 1775, Wattenwil, Bern, Switzerland. However, this George dies 03 SEP 1853 and was married to Christine Zimmerman.
1801, Marriage to MARY SCHAFER (presumably later known as Polly) aka Anna Marie Shaffer. German Reformed Church, Frederick, Frederick, Maryland, according to record on familysearch.org.
Possibly father to Solomon Messerly (c1805) born 1805 MD listed as Imperly in the 1850 Census. He is in same township as father in 1850.
George and his son George were named in a will by the name of Conrad Dotterer. Others named in the will was a family by the name of Shaffer. The wife of George was named as Anna Marie Shaffer originally from Frederick, Maryland. source
Obit for George's son George: MESSERLY. On the 2d of August, 1892, in Beaver township, Mahoning Co., of dropsy, George Messerly, aged 77 years, 6 months and 9 days. Interment at the Paradise (Reformed) church where services were held by J. M. Kendig. Herald of Truth , Vol. XXIX, No. 17, September 1, 1892 page 268. 269, 270 link