The Altemus & Co. imprint can be found on Photographic albums, scrapbooks and a handful of other publications. Books with this imprint are quite scarce. Here is an example of a book with the Altemus & Co imprint. This title was first published by Hogan and Thompson, a Philadelphia publisher, in 1851.
The date of the Altemus publication is unclear. Based on the use of this imprint plus the style of the book a date between 1851 and the 1870’s is my best guess.

This is definitely the earliest Altemus & Co imprint that I have seen with exception of some photographic albums.

The book (The Talisman) has gold gilt edges and measures 6.5 x 9.5.