I have lots of Calders from Forfar so I wonder if there is a connection.

Mine go back to Alexander Calder in the 18th century. His son George (b 1787) married Elizabeth Williamson also from the Forfar area and they had 10 children. I have traced some of the descendents to Australia, some to South Africa and some still live in Aberlemno near Forfar.

Let me know if you have any other names and dates to see if we cross over at any point