Grammar Question - Help Appreciated!

[Elliebelly]

Hi, can anyone tell me whether this sentence is grammatically correct, please?

"Littering the approaches to the horseshoe harbour of Australia's Mawson Station during the brief summer thaw are any number of tiny rocky islets, as yet still not completely logged on hydrographic maps, each a potential threat to shipping."

I tend to overdo it with commas, so I'm not sure if I'm correct with wanting to place a comma after "Station" and also after "thaw". Also, is the comma after "islets" the correct use of punctuation? I'd really appreciate your help!

[emsr2d2]

Looks good to me.

[Elliebelly]

Hi, emsr2d2! Thank you so much for your answer. I'm grateful for your speedy reply.