1. the caves are dug in the rocks of the family of limestones
2. The limestones rocks do not exist everywhere. In particular, the Vosges, Brittany and the Central Solid mass, which are granite areas, that do not possess limestone.
3. Limestones have the characteristic to be dissolved by the acids, like the vinegar. They are also permeable rocks, thanks to the breaks (faults, fractures, cracks) which traverse them. However the water which traverses them is acid thanks to the carbon dioxide which it dissolved in the crossing of the ground. Thus, water dissolves limestone while circulating in the cracks which it widens until creating the caves.
4. One calls “Karst” a landscape that is formed in the limestones rocks with a morphology of surface (depressions, valleys plug...) and an underground morphology (caves, pits, underground rivers) defined by phenomena of dissolution related to water. However, the term of karst is used only if these forms constitute a unit which is structured and arranged hierarchically.
5.5. The subsoil water comes from the rain which penetrates into the rock, by the cracks or the pores, or which penetrates under ground in more localised points starting from the flows of surfaces

lists of the caves in France :
France Ouest

Name of the Site	Adress	TEL	FAX
GROTTE DE BARA-BAHAU	Proumeyssac, BP7 Le Bugue 24260.	0553072747	0553547503
GROTTE DE BETHARAM	65270 - Saint-Pé-de-Bigorre	0562418004	0562418725
GROTTES DE COUGNAC	46300 Payrignac	0565414754	0565414754
GROTTES DE FONTIROU	Castella 47 340	0553401529	0553417397
GROTTE DU FOULON	35, rue des Fouleries 28 200 Chateaudun	0237451960	0237458002
GROTTES PREHIST. DE GARGAS	65640 - Aventignan	0562397239
GROTTES D'ISTURITZ OXOCELHAYA	Oxocelhaya, 64640 - St Martin d'Arberque	0559296472	0559473017
GROTTE DU GRAND ROC	24620 - Les Eyzies	0553069270	0553351755
GOUFFRE DE PROUMEYSSAC	24260 - Le Bugue	0553072747	0553547503
GROTTE DE ROQUE ST CHRISTOPHE	Peyzac le Moustier 24 260 Les Eyzies	0553507045	0553510321
GROTTE DE ROUFFIGNAC	24850 - Rouffignac St Cernin	0553054171	0553354471
GROTTES DE SAVONNIERES	Place L. Reverdy 38360 Savonnières	0247500009	0247500103
GROTTE PREHIS. DE VILLARS	Villars 24530	0553548236	0553542173
GROTTE DE LACAVE	46200 - Lacave	0565358703	0565331678
GOUFFRE DE LAFAGE	19600 - Noailles	0555858035
GROTTE DE MEDOUS	Quartier Médous 65200 Aste	0562917846	0562950203
GOUFFRE DE PADIRAC	46500 - Padirac	0565336456	0565337186
Gouffre géant de Cabrespine	BP2 11 160, Cabrespine	0468261422	0468261075
GROTTE DE PECH MERLE	46330 Cabrerets	0565312705	0565312047
GROTTE DE PRESQUE	BP 51. 46 400 St Céré	0565380744
SITE PREHIST. DE CASTEL-MERLE	24290 - Sergeac	0553507970
GROTTES DU CORNADORE	63710 - ST NECTAIRE	O473885166	0473885431
Abri Préhistorique du CAP BLANC	24620 Marquay les Eyzies	0553592174	0553283954
GROTTE PREHISTORIQUES DES MERVEILLES	46500 Rocamadour	0565336792	0565336792
MOULIS	09200 St Girons	0561663126	0561960851
GROTTE de REGOURDOU	24290 Montignac s/ Vézère	0553518123	0553518123
GROTTE de ROLAND	46800 Montcuq	0565229990
GROTTE PREHISTORIQUE de SARE	64310 Sare	0559542188	0559542069
GROTTE et CANYON de SAULGES	53270 Thorine-en-Charnie	0243905229	0243905544