Guardian 25083

[baibee]

15d Don't talk about entering footwear for native Americans 9 S _ O _ H _ _ _ S must be a sh in it somewhere
13a St Peter, etymologically, to scrub the deck 9 H _ L _ S _ O _ N _ E
and 2d First class student on trees races round backwards 4 5 T _ I _ / _ _ R _ T
Thankyou

[kayakamina]

15d Shoshones

13 Holystone

2 Tail first

[baibee]

Never heard of Shoshones though realised it was something to do with shoes and sh.
As for tail first, it's unusual to have so much of the answer in the clue ie first - that confused me a bit.
Can you give me 3d and 24a then I'm finished. No idea what the English river - English river with gravelly deposit is, though have E _ K _ R
and 24a Security device keeps prisoner from drug 7 S _ C _ N _ L

[kayakamina]

3d Esk (river) +E (english) R (river) = Esker - deposit

24a Se con al - Drug ...Con (prisioner) in SEAL (security device)