Madagascar - Cliff and caves of Isandra

The Cliff and Caves of Isandra are both a natural site (I) and a fortified archaeological site (II) integrated into the landscape of the picturesque rocks of the valley of the small river Isandra. (I) View of the valley, an impressive vertical cliff overlooking a large berm with huge rock wedges embedded in a granite chain oriented north-south. This relief is explained by a differential erosion in the migmatites and granites of the crystalline basement. The forms of erosion of the large cliff are runoff grooves, taffoni perforations can reach a large size (2 to 3 m of opening and as much depth) and especially large rock falls due to dia-clases. Over the course of successive landslides was then built at the foot of the cliff an enormous heap of granite blocks with interior voids that can serve as shelters: the "caves", used by the ancient inhabitants in the seventeenth and eighteenth century. A.D. (II) Because of the defensive possibilities offered by the particular layout of the enormous rocky slopes fallen from the cliff, the ancient inhabitants once settled there by creating an original and ingenious fortified site. They took advantage of the impressing chaos of granite blocks to organize the fortified village. They built protective enclosures of dry stones between the blocks, built terraces of habitat with dry stone retaining wall. In addition, the natural layout of the blocks has made it possible to build a large number of rock shelters that contemporaries have wrongly called "caves". The originality of the site also lies in the maze of cavities, sometimes impressive, corresponding to the interstices between the blocks of rocks; these cavities were used for different purposes: here shelters (habitat ?, there are access roads to other places of habitat somewhere in the chaos, elsewhere dumps for the inhabitants ... Finally, the taffoni of the cliffs were used once to bury certair dead.