Click on this map to get a larger version – and read the legend.  The original citation can be found here.  The large pink area on the eastern side of Madagascar is granite or similar rock forming the core of the mini-continent of Madagascar.  Red is volcanic rock – though nothing is really recent.  The orange is sandstone – Isalo National Park is basically all eroded sandstone formations.  And the light and dark blues are limestone – the tsingy formations are the light blue areas.  Alluvium (eroded material like sandy flats and sand dunes) are yellow.  Note that the sedimentary rocks (sandstone and limestone) are on the westrn side of the island while the igneous rocks that cooled from molten magma (mostly deep underground as with granite) are on the eastern side of the island.

Google Earth view, dark areas are forested, light are grasslands or less vegetation.  Our route and the nightly stops are indicated.

Oct-April mean cloudiness (warm season). Red max cloudiness, blue is minimum. Note that west coastal region is still a minimum in daytime cloudiness – associated with sea breeze subsidence.