1. Placed hoop round belemnite (10 letters)
8. In a lad yet a lass (4)
9. Sitting untruly (5)
11. Minimum tide (4)
13. Hidden in mind (2)
14. Led lotex back and sang the praises of (8)
16. Lost the way in byway (2)
17. A Gilbert and Sullivan princess (3)
19. All ears (5)
21. Sound of a stream knitting (4)
22. Thus solo less lo (2)
23. A nitrite to ease the heart (4)
25. Count vote for head tax (4)
27. Messy logo I turn around for earthshaking study (10)

Clues down

1. Scare lad into deep depressions (8)
2. Indicator (7)
3, 16. Global loam suddenly around on water surface (5, 5)
4. Comes before te doh (2)
5. Initially an overdose (2)
6. I dig up my trilobite tail (8)
7. Not night (3)
10. New prefix (3)
12. Apply in a layer (3)
15. See 18 down
16. See 3 down
18, 15. Very lady L. up opposite a wet ridge (3, 6)
20. Pass over Cleopatra's pets (4)
21. Help all in, become wearisome (4)
24. First person were in us (2)
26. Solo less so (2)