This paper is a study of the importance of the previous topography in the installation of the volcanoes. For this, the form and size of 297 monogenic cones in Tenerife have been observed. When the eruptive centers are located in sectors with gentle topography, the morphology of the cones tend to be of ring type and in typical horseshoe-form, they have scarce elongation and little span and in general they are small symmetrical buildings. On the contrary, when the topography is significant, the form of the piroclastic cones is less symmetrical and the buildings are mainly opened up in diapason, arch, horseshoe and multiple, they are also more elongated an larger.
