This morning I checked "The Blacks in Canada: A History" by Robin Winks and found a mention of John Highgate in the Chatham area 1906. In reference to African Canadians who were prospering, it says:

"John Highgate of Dover Centre who owned a hundred acres and a prize stud;..." pg 328

There is also the town of Highgate, I believe now a part of Chatham, which is likely a connection:

http://www.chatham-kent.ca/recreation+and+tourism/events+and+travel+guide/community+overview/Highgate.htm