Bohol has become synonymous with Chocolate Hills located northeast of Tagbilaran, the provincial capital. Clusters of these cone-shaped mounds are scattered over about 50 square km. (about 30 sq. m.) around Sagbayan, Carmen, and Sierra Bullones in Central Bohol. Numbering 1,268 in all, the hills are formed of sedimentary limestone, shale, and sandstone in an area once covered by ocean. Each hill rises 30-120 meters (100-400 ft.) above the flat terrain. The hills are green during wet weather, but after a dry spell, which is most likely to occur in April and May, the sparse grass cover turns dry and brown so that they resemble chocolate drops, hence the name.
The explanation of their geological formation remains a mystery. Some theories postulate prehistoric, submarine volcanic eruptions and the action of sea currents, but most geologists believe that weathering is the main factor. Curiously, although they’re regarded as an example of karst topography, none of the hills contain caves.
The hills are also the subject of numerous legends. Teardrops from a lovelorn giant helped form the hills. Another one has it that they were strewn across a battlefield where two giants threw rocks at each other.
Any idea how it was formed?
Inside Guide Philippines by Discovery Channel
Philippines Handbook by Carl Parkes