June 10, 1838
Selvey K. Blodgett, Jr. was born in a log house, the second white child in Beloit.
The evidence
“Blodgett, the father of William, arrived from Ohio and engaged in farming on the place now known as Yost's park. Here in a log house was born the second white child in Beloit, William's brother, Selvey K., Jr., June 10, 1838.”
1908-brown-rock-county/34c-biographical-3.md, Vol. 2, PDF p. 433 / book p. 924
Brown, William Fiske, editor. Rock County, Wisconsin: A New History of Its Cities, Villages, Towns, Citizens and Varied Interests, from the Earliest Times, Up to Date. Chicago: C. F. Cooper & Co., 1908. 2 vols. archive.org/details/rockcountywiscon01brow, archive.org/details/rockcountywiscon02brow.
Grade A: Found on a page of one of our sources
On the printed page (Vol. 2, PDF p. 433 / book p. 924) · open the whole page “Rock County, Wisconsin; a new history of its cities, villages, towns, citizens and varied interests, from the earliest times, up to date . w known as Yosts park. Here in a log house was bornthe second white child in Beloit, Williams brother, Selvey K., Jr.,June 10, 1838. Caleb Blodgett had named the settlement New Albany, butthe later arrivals in the village disliked that name, so that inthe fall of 1838 a committee of three chose the new name, Beloit. In Caleb Blodgetts house, using Calebs large family Bible,twenty-four members founded the First Congregational churchof Beloit, December 30, 18 Stock Photo - Alamy Hi there! Lightboxes Share Alamy images with your team and customers Create a lightbox ›”
alamy.com, https://www.alamy.com/rock-county-wisconsin-a-new-history-of-its-cities-villages-towns-citizens-and-varied-interests-from-the-earliest-times-up-to-date-w-known-as-yosts-park-here-in-a-log-house-was-bornthe-second-white-child-in-beloit-williams-brother-selvey-k-jrjune-10-1838-caleb-blodgett-had-named-the-settlement-new-albany-butthe-later-arrivals-in-the-village-disliked-that-name-so-that-inthe-fall-of-1838-a-committee-of-three-chose-the-new-name-beloit-in-caleb-blodgetts-house-using-calebs-large-family-bibletwenty-four-members-founded-the-first-congregational-churchof-beloit-december-30-18-image338198796.html
Grade B: Found on an institutional web page