Abandoning the main road (towards Portella Colla), after a few metres you have to turn left. You will find yourself in a thick wood. After walking some 500 m you are at Portella Arena. Here the landscape is completely different from the previous area. Light grey-whitish dolostones and dolomitic breccias (Quacella Formation, aged Upper Triassic - Lower Jurassic) outcrop. The dolostones are powdery and greatly weathered. The dolostones were formed in a shelf margin of the carbonate platform. In this area carbonatic breccias coming from the near reef complex accumulated in large amounts. The dolostones lack clear evidence of fossils owing to heavy dolomitization processes that have nearly obliterated the rock's original texture. Here you can see isolated needle rocks due to selective physical weathering, such as frost wedging, that evolved more strongly along the faults and joints of the rock. You can also see these landforms along the western slope of Monte Mufara.