For the teaching in/on

[Xinfu]

In an email beginning to thank the teacher, are they correct?

-Thank you for your teaching in ___ (a course name like 19th Century Fiction or Special Topic in Danish Literature) in the previous term.
-Thank you for your teaching on ___ (a course name like 19th Century Fiction or Special Topic in Danish Literature) in the previous term.

[poli]

of is the preposition

[Rusty]

No preposition is needed.

Thank you for teaching 19th-century Fiction last term. (simple and straight-forward)
Thank you for your teaching English ... ('your teaching' is possible)

After 'your teaching', you can say 'of' if a course name is used.

To use 'in', you need to change 'teaching' to 'teachings', but 'instruction' or 'lessons' sounds better.
Thank you for your instruction/lessons in Danish Literature'.

To use 'on', 'lessons' can be used.
'About' may be substituted for 'on', with 'instruction' or 'lessons'.

[Xinfu]

Thank you.