Alright, we need to start genning worlds with no Caverns, and no Erosion. WE MUST CONTINUE THIS EPICNESS.
That may not be necessary...
I genned a world with Caverns & what not where, AFAICT, none of the Volcanos showing on the Region Map show on the Local Map.
The one I embarked on in search of a volcano (8x8, 'cos 16x16 was crashing & I just wanted to know where the volcano was for a smaller embark) was nearly 1/4 Magma sea (@ ~= -90z), & another 1/4... Eerie Glowing Rock (@ ~= -101z).
I didn't notice any Clownite though.
Created in DF v0.31.14.
[WORLD_GEN]
[TITLE:GORKYPARK]
[SEED:1597527813]
[HISTORY_SEED:2290366999]
[NAME_SEED:1985429190]
[CREATURE_SEED:1756313460]
[DIM:129:257]
[EMBARK_POINTS:1274]
[END_YEAR:199]
[BEAST_END_YEAR:2:-1]
[REVEAL_ALL_HISTORY:1]
[CULL_HISTORICAL_FIGURES:1]
[ELEVATION:1:400:401:800]
[RAINFALL:0:100:200:400]
[TEMPERATURE:35:55:200:400]
[DRAINAGE:0:100:200:400]
[VOLCANISM:0:100:200:400]
[SAVAGERY:0:50:200:400]
[ELEVATION_FREQUENCY:1:1:1:1:1:1]
[RAIN_FREQUENCY:1:1:1:1:1:1]
[DRAINAGE_FREQUENCY:1:1:1:1:1:1]
[TEMPERATURE_FREQUENCY:1:1:1:1:1:1]
[SAVAGERY_FREQUENCY:1:1:1:1:1:1]
[VOLCANISM_FREQUENCY:1:1:1:1:1:1]
[MEGABEAST_CAP:32]
[SEMIMEGABEAST_CAP:72]
[TITAN_NUMBER:12]
[TITAN_ATTACK_TRIGGER:80:0:100000]
[DEMON_NUMBER:12]
[GOOD_SQ_COUNTS:50:501:1003]
[EVIL_SQ_COUNTS:50:501:1003]
[PEAK_NUMBER_MIN:0]
[PARTIAL_OCEAN_EDGE_MIN:1]
[COMPLETE_OCEAN_EDGE_MIN:0]
[VOLCANO_MIN:200]
[REGION_COUNTS:SWAMP:518:3:3]
[REGION_COUNTS:DESERT:518:3:3]
[REGION_COUNTS:FOREST:2072:6:6]
[REGION_COUNTS:MOUNTAINS:4144:4:4]
[REGION_COUNTS:OCEAN:4144:3:3]
[REGION_COUNTS:GLACIER:0:0:0]
[REGION_COUNTS:TUNDRA:0:0:0]
[REGION_COUNTS:GRASSLAND:4144:6:6]
[REGION_COUNTS:HILLS:4144:6:6]
[EROSION_CYCLE_COUNT:128]
[RIVER_MINS:800:800]
[PERIODICALLY_ERODE_EXTREMES:0]
[OROGRAPHIC_PRECIPITATION:1]
[SUBREGION_MAX:5000]
[CAVERN_LAYER_COUNT:3]
[CAVERN_LAYER_OPENNESS_MIN:90]
[CAVERN_LAYER_OPENNESS_MAX:99]
[CAVERN_LAYER_PASSAGE_DENSITY_MIN:1]
[CAVERN_LAYER_PASSAGE_DENSITY_MAX:10]
[CAVERN_LAYER_WATER_MIN:10]
[CAVERN_LAYER_WATER_MAX:90]
[HAVE_BOTTOM_LAYER_1:1]
[HAVE_BOTTOM_LAYER_2:1]
[LEVELS_ABOVE_GROUND:9]
[LEVELS_ABOVE_LAYER_1:8]
[LEVELS_ABOVE_LAYER_2:4]
[LEVELS_ABOVE_LAYER_3:4]
[LEVELS_ABOVE_LAYER_4:4]
[LEVELS_ABOVE_LAYER_5:2]
[LEVELS_AT_BOTTOM:1]
[CAVE_MIN_SIZE:10]
[CAVE_MIN_SIZE:10]
[CAVE_MAX_SIZE:100]
[MOUNTAIN_CAVE_MIN:50]
[NON_MOUNTAIN_CAVE_MIN:100]
[ALL_CAVES_VISIBLE:0]
[SHOW_EMBARK_TUNNEL:2]
[TOTAL_CIV_NUMBER:96]
[TOTAL_CIV_POPULATION:15000]
[SITE_CAP:512]
[PLAYABLE_CIVILIZATION_REQUIRED:1]
[ELEVATION_RANGES:4144:8288:4144]
[RAIN_RANGES:4144:8288:4144]
[DRAINAGE_RANGES:4144:8288:4144]
[SAVAGERY_RANGES:4144:8288:0]
[VOLCANISM_RANGES:4144:8288:4144]