Which preposition to use with surmisings

of Occurrences 1%

He severely condemned causeless jealousies and evil surmisings of every kind, and extended that charity, in this respect, both to clergy and laity, which good Bishop Burnet was so ready, according to his own account, to limit to the latter, "of believing every man good till he knew him to be bad, and his notions right till he knew them wrong."

to Occurrences 1%

" Sir Giles rounded upon him with a violence that brought his surmisings to an abrupt end.

Which preposition to use with  surmisings