Scholars studying early distribution of Native groups and languages in Chukotka have been for long discussing the value of several early-contact records left by the Russian explorers and other visitors to the region during the 1700s and early 1800s. This paper offers the first detailed analysis of one of such early scholarly records produced by Carl Heinrich Merck, a German doctor and natural scientist, who visited Chukotka in 1791. Specifically, the author reviews a word-list of several dozen Native terms in Merck's manuscript belonging to the so-called "Uelenski language." Based upon comparative analysis, he argues that the "Uelenski language" was actually, a dialect of the Central Siberian Yup'ik that once used to be spread widely along the eastern and northern shores of Chukotka. Later population replacements, language and cultural shifts have changed the linguistic map of the region, leaving Merck's manuscripts as the only indisputable evidence of the early Siberian Yup'ik presence at Bering Strait and along the Arctic coast of Chukotka.