> but we do keep phrases with that ordering from Middle English (e.g. Surgeon General)

That's not from Middle English, it's from French.

Which Middle English was heavily influenced by.

Middle English was closer to French than modern English in many ways-English monarchs still spent time in Normandy and claimed the French crown for generations after William the Conqueror.

Can you provide some citations for locative prepositions appearing before their nouns? I am not widely read in classical Chinese, but all the examples I've turned up have used the normal order.

e.g. 孟子 1A/3 河內凶，則移其民於河東，移其粟於河內 (strongly suggesting that the current naming practices were also current 2200 years ago); 庄子 秋水 13 我知之濠上也 (ordinary positioning).

You're totally right, I was confusing modifiers with Chinese's general looseness towards word class, a tendency even more pronounced in Classical Chinese [1]. That means what looks like modifier/preposition could be functioning as a verb instead.

So my mother-in-law just said '上海不在海上', i.e. 海上 is closer to the literal meaning of 'on top of the ocean (physically)', which the city is not.

Perhaps 上 here acts as a verb or gerund ((going up / on the way) to the ocean)? 下海 means 'going (down) to the ocean'.

The rabbit hole here can get deep (and thanks for drawing me in!), this book [2] goes in-depth about how word class and word order influenced one another as Chinese developed.

[1] https://en.wikipedia.org/wiki/Classical_Chinese_grammar#Word...

[2] https://www.google.com/books/edition/_/r9WO6g5mqi8C?hl=en&gb...

> Perhaps 上 here acts as a verb or gerund ((going up / on the way) to the ocean)? 下海 means 'going (down) to the ocean'.

This is possible, but I don't think it's a coincidence that the normal way to express that is 下海. The ocean is pretty much by definition both "down"stream and downhill of everything; approaching the ocean by going up is semantically unnatural. My guess above of "get onto the ocean" (i.e. "set sail") was drawing a parallel to 上路 "get on the road" / "start traveling".

> 海上 is closer to the literal meaning of 'on top of the ocean (physically)', which the city is not.

I don't see this as a huge obstacle; "upon the sea" has the same literal meaning but isn't surprising in an English place name, though "by the sea", with the correct literal meaning, isn't surprising either.