Celestia Bloss Brewster began her teaching career as tutor to her brother-in-law Isaac Moore's children in his home. Other neighborhood children began attending the classes, and when the meetings became too large for Moore's home, Moore made her a gift of five acres at Clover and Elmwood Streets in Brighton to build a school. The Clover Street Seminary opened in 1848; although Celestia fought valiantly to have it be co-educational it became a girls' school. However, it quickly gained such a fine reputation for its high educational standards for women that young ladies were sent from well to do families all over the country to attend its classes. After Celestia's early death from consumption at just 43 years, the Seminary eventually became St. Mark's School for Boys.
Inscription: "She was not slothful in business Fervent in Spirit serving the Lord
This monument erected by her pupils, an enduring testimony of their affection and respect."