The gestation period for an elephant is 640 to 660 days. This is equivalent to about 95 weeks, or 22 months, and is the longest gestation period of any mammal.
Dimes dated after 1964 are copper-nickel clad and contain no silver. Quarters are also clad, except for the bicentennial commemorative coins with an S mint mark that were produced for mint and proof sets. Kennedy half dollars from 1965 to 1970 were 40 percent silver composition. After 1970, all Kennedy halves were clad, except the same S bicentennial issue.
What year did they stop making silver quarters? 1964 was the last year for circulating silver quarters, as well as  dimes. Half-dollars were 40% silver clad until 1971. Since 1992,  though, Proof silver quarters, half-dolâ¦lars, and dimes have been  offered to collectors through the US Mint. (MORE)