Here is some trivia on notes on Gleason's Map.:
"Modern" is a common mis-spelling of "Morden", as in Morden College
Morden College, in Blackheath, England, is a charity organization for a home for "retired merchants who have lost their estates."
The term "College" is in no reference to an institution of higher learning such as a college or university, but in the sense of being a "collegiate" type organization.
Morden College was established in 1695 by Sir John Morden.
Joseph Streep Christopher was a retired merchant who was an "inmate" of Morden College from 1875 to 1894 until his death at the age of 89. His application for membership in Morden College only lists him as a retired merchant.
No information was found as to any connection with cartography in reference to the map.
No information was found as to any connection between Gleason and Christopher to the map .
"There is also a letter from a Trustee, H.B. Heath, to our then Treasurer , written in 1890.:
'As a matter of curiosity, can you tell me which of the inmates of the College entertained the theory that the earth is flat ? Not Mr. Christopher ? '"
-The above information was supplied by research personnel at Morden College