What was unusual about the 1866 and 1867 Melbourne Cups?

In 1867 the Melbourne Cup had two horses completed bearing the name Tim Whiffier. To avoid confusion they were called "Sydney Tim" and "Melbourne Tlm". The Sydney Tim Whiffier started favourite at 5-2 and won. The Melbourne Tim Whiffier ran fifth. The Cup that year was run on Thursday, October 31. In 1866 two horses named "Falcon" ran in the Melbourne Cup.

Close enough to earn a lower case yay! the two
involved in the 1867 race were both called Tim Whiffler. A painting of Sydney Tim's dam hangs in
the committee room of the Victoria Racing Club.
It's called Whiffler's Mother.