The novel has a mixed narrative and anthropological style: the fast-paced plot is periodically interrupted with descriptive scenes and commentary so that 19th-century white readers can feel that the novel is bringing them into contact with the "lost world" they have (in their minds) inherited. For example, in Volume 1, Chapter 7, the narrator describes the village where Mononotto has taken Faith and Everell:
Little garden patches adjoined a few of the dwellings, and were planted with beans, pumpkins, and squashes; the seeds of these vegetables, according to an Indian tradition, (in which we may perceive the usual admixture of fable and truth,) having been sent to them, in the bill of a bird, from the south-west, by the Great Spirit.
The narrator begins with description and then interrupts the description to address the origin of the bean, pumpkin, and squash seeds: supposedly, a deity sent a bird to carry them to the Mohawk people. As this origin story is unfolding, the narrator also intrudes to undercut it. As is usual, the narrator claims, this story told by American Indians contains an "admixture of fable and truth." This interjection positions "we" (the narrator and the reader together) in a cultural category separate from "Indians." Sedgwick has already established in the preface that she is taking 19th-century readers on a tour of the 17th century. To this end, she also describes Puritans anthropologically, with a combination of awe and disdain. In the above quote, she seems to be taking non-Native readers (probably white readers) on a tour of American Indian tradition.
The idea that Sedgwick, a white woman, is an authority on "American Indian tradition" suggests that she thinks of American Indian cultures as relics that need her help to be excavated from the past. She speaks about this story as an "admixture of fable and truth," as if American Indian people themselves cannot speak or be consulted on their own history. She imagines that her work as a novelist is to use a sensational narrative to preserve, for white readers, the cultural memory of the people they have "replaced" as inhabitants of North America.
In fact, even the narrator's use of the term "Indian tradition" reinforces the novel's anthropological style. The idea of a singular American Indian identity is tied to colonization of the Americas: American Indian nations themselves are culturally diverse. A unified "Indian tradition" is largely a fiction European colonists imagined to make sense of their cross-cultural encounters. The history of American Indian identity has become far more complicated than this, but Sedgwick is simplifying the political and cultural landscape of North America (for instance, she uses colonists' names for various nations and is not always precise about which nations she is describing). Her simplification marks out her position as a white person speaking to other white people about a culture (or cultures) to which they do not belong.