This question can be answered with reference to the second paragraph of Chapter 1. Having introduced the setting and the time period within which the story was set, the narrator then introduces the main character to her readers in the following way:
In the early years of this century, such a linen-weaver, named Silas Marner, worked at his vocation in a stone cottage that stood among the nutty hedgerows near the village of Raveloe, and not far from the edge of a deserted stone-pit.
Silas Marner was therefore a "linen-weaver" who worked in his stone cottage near Raveloe, and was one of the linen-weavers that Eliot talks about in her opening paragraph. She describes that weavers appeared almost alien because of the paleness of their skin through staying indoors so much working on their machines, and certainly Silas Marner is no exception. As a weaver, he spends the majority of each day inside, away from light, working on his loom, weaving, and as a result has rather an odd appearance.