Fifteensquared

A well-crafted tour through a variety of avenues of general knowledge today.  We seem to cover everything from military history to folklore and geology, by way of a healthy dose of geography along the way.

Across
1 ROMMEL – {S}omme in R+L (“opposing sides”).  Aka the Desert Fox.
4 CATHOLIC – (at H) in colic.  The definition relates to the uncapitalized version of the answer.
10 ST LUCIA - (A1 cults)<.  If you’re a beer snob, then I strongly recommend trying to get your laughing gear around a bottle of Piton Beer one of these days.
11 PARABLE – Para(trooper) + B{i}L{l}E{t}.
12 MOCK – double def’n.
13 FRITILLARY - till in friary. I was only familiar with this word as a type of butterfly, rather than in the botanic sense.
15 RAISIN – {Con}is{ton} in rain.
16 STIPPLE – tipples, in arse-over tip fashion.
20 MENTION – I in Menton.
21 KORUNA – (o + run) in Ka.  The Czech “crown”.  Took be a minute or two for this expat to recall the (Ford) Ka.
24 OUTCLIMBED - be{n} in (Tim cloud)*.
26 AMID – am + id.
28 TABLEAU - able in Tau.
29 PIT BULL – (but)* in pill.
30 MERRY MEN – merry + {o}men.
31 URCHIN – {l}urchin{g}.

Down
1 ROSEMARY – r.o. + sem{in}ary.
2 MALACHITE - (a chit) in (meal)*.
3 EACH – {t}each.
5 APPETITE – (pet in pit) in A+E.
6 HARTLEPOOL - R in (The Apollo)*.  Alias the Monkey Hangers, within the realms of lower league football.
7 LIBYA - Lib + (ay)<.  I initially wondered if this was an error, until I looked up confirmation that “ay” is a valid alternative spelling of “aye”.
8 CHERYL – hidden.  Exemplified by Ms Baker or Ms (soon to be ex) Cole, depending on your own pop culture vintage.
9 SABRE - (bares)*.
14 DISTILLERY - still (i.e. not sparkling water) in die + ry.
17 LOUDMOUTH - (D{ublin} + m{erely} + {h}ou{r}) in Louth. An interesting device with the “half” in “half an hour” referring, unusually to the central 50%, rather the front- or back-end.
18 DORMOUSE - dorm + ouse.
19 MANOLIN - {a]L{ter} in man doin’.  Not a big personal fan of “second to” as a logical equivalent of “second of” or “second in”.
22 TOM-TOM – not a bad pun.
23 TEMPO - T{ynesid}E + MP + o{bserves}.
25 TUBER – rebut<.
27 STAR – rats<.