Q. David Bowers (edited and updated by Mike Sherman): The Liberty Seated dollar design was modified in 1866 by the addition of the motto IN GOD WE TRUST on the ribbon or scroll above the eagle on the reverse. Otherwise the design is the same as that which had been in use since 1840. The With Motto type continued in use through 1873.
The glory days of the silver dollar denomination were yet to come, and mintages were low in comparison to what would happen with the Morgan silver dollar beginning in 1878. The only “common” Liberty Seated dollars in this range are the 1871 and 1872, and even they are scarce in relation to later issues. The 1870-S is one of the legendary rarities in U.S. numismatics, with only about a dozen pieces known. The few Carson City issues (1870-1873) are also quite tough, with miniscule original mintages.
As Liberty Seated silver dollars did not circulate as actively as smaller denominations, pieces in well-worn grades such as Good and Very Good are much scarcer (though no more desirable or expensive) than coins in Fine to Very Fine grade, the latter being the conditions typically seen. Extremely Fine and AU pieces are available, with Uncirculated pieces being somewhat scarcer, though by no means rare. Superb Uncirculated pieces are fairly rare. Proofs were made of all Philadelphia Mint issues, and exist today in proportion to their original mintages.
-- Reprinted with permission from "United States Coins by Design Types - An Action Guide for the Collector and Investor" by Q. David Bowers