I pulled this image from Markus Bertelsmann’s facebook images, and it is labled: Missale Carnotense (Codex Chartres 520); Faksimile. Das Original dieser unschätzbar aufschlußreichen Handschrift verbrannte 1945 mit der Bibliothek von Chartres.
Missale Carnotense
A quick translation (with a little help from Google): "The original of this invaluable manuscript was lost in 1945 in the burning of the Library of Chartres."
Interesting diastematic neumes with two lines for reference. Interesting that it dates from the first half of the 13th century when notation had developed fully.
I saw a leaf from 12th c. German/Polish monastery with nondiastematic neumes a few months ago. It hung around for a while.