Acknowledgements
The field trip has been realized in Sardinia during the summer 2006 as part of the projects funded by MIUR “Azioni integrate Italia- Spagna” and PRIN-Cofin 2004.
We greatly appreciated comments and fruitfull discussions either in field or in the universities in a number of different occasions with J. Carreras, L. Cortesogno, A. Di Pisa, E. Druget, M. Franceschelli, L. Gaggero, C. Ghezzo, F. Giacomini, A. Griera, R. Law, G. Oggiano, R. Palmeri, C.W Passchier, P.C. Pertusati and C.A. Ricci.
Financial support was provided by MIUR-PRIN 2004 (Resp. R. Carosi) and University of Pisa.