Gavel used at first Nebraska Unicameral
In the early 1930s, Nebraska U.S. Senator George Norris promoted the concept of the non-partisan, one-house legislature called the Unicameral. He believed that a one-house system would curb abuses of the conference committee which had allowed the majority party to rewrite legislation to favor its own positions. In 1934, Nebraska voters enthusiastically endorsed the idea and in 1937 Nebraska became the first and only state to have a unicameral legislature. This gavel opened the first unicameral legislative session on January 5, 1937.
Source: Senator and Mrs. George W. Norris (9173-4)