Quantitative data on rock surface millimetre-scale roughness are presented concerning the splash and spray geomorphologic domains of two coastal profiles developed on Mediterranean carbonate rocks. Differences of the roughness characteristics are attributed to rock properties, weathering agents and bioerosion. In the splash zone, roughness is related to sparsely distributed patterns of bioerosion, salt weathering and wave attack. In the spray zone, smooth surfaces seem to be the response to the solution processes that predominate, exerting a more homogenous influence on rock surface evolution.Mallorca is the largest island of the group of islands known as the Balearics (western Mediterranean), which also includes Menorca, Eivissa, Formentera and Cabrera, and they are the most isolated group of the Mediterranean islands. The island of Mallorca covers 3644 km 2 and its coastline is 565 km in length. The island's southeastern coast is characterized by vertical coastal cliffs of more than 30 km in length with elevations ranging between 5 and 56 m. The rocks outcropping in the cliffs of this area correspond to the uppermost Upper Miocene succession. These sedimentary rocks form a quasi-tabular kilometre-scale relief (Marina) which corresponds to the southeastern progradation of a reef complex over a pre-orogenic basement (Pomar et al., 1983). In a series of nearly 60 m thickness, that outcrops over the sea, two different sequences can be observed. At the base, the Reef Unit is composed of massive crystalline reefal limestone. Above this, and lying in unconformity over a karstic surface, is the Terminal Complex, composed of a well-bedded alternating calcarenite and calcisiltite, while a massive bed of oolitic limestone (Pomar, 1991) forms the remainder of the cliff.Both study sites, located on the southeastern coast of Mallorca (Figure 1), are related to the geological units and rocks described above. Although both rock outcrops consist of Miocene calcarenites, the major differences between them are related to textural characteristics due to the differing mud and faunal content ( Table I). The S'Alavern study site is located in the south of the island, where shore platforms are well developed and range from 9·70 to 13·20 m in width. Going inland there is an inherited 10-m-wide shore platform, 1-2 m above sea level, with a cliff 10 -15 m in height. The second study site, Cala Murada, is located in the eastern side of the island. This coast sector is characterized by narrow shore platforms, backed by a stepped cliff 5 m in height. Figure 2. Box graphs of index A (see explanation in the text) for (a) Cala Murada and (b) S'Alavern.micro-reliefs. Differences in weathering agents and processes across the shore profile have been described by water chemistry analysis and X-ray diffraction (Moses and Smith, 1994), and by SEM observations (Gómez-Pujol and Fornós, 2004). Thus at the splash domain, intensive biological colonization enhances the role of bioerosion by grazing and rock-inhabiting organisms (Schneider and Torunski, 19...