Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2009.; Cataloged from PDF version of thesis. Original thesis missing page 1, the Abstract page.; Includes bibliographical references (page 32).; Introduction - The Beni Bousera ultramafic massif is an orogenic lherzolite in northern Morocco, and is part of a large series of ultramafic massifs (Chalouan and Michard, 2004). Like all orogenic lherzolite the method of emplacement into the upper crust is not well understood (Reuber et al., 1982). In this thesis, the Filali gneiss, Kinzingite gneisss, and leucocratic dikes were studied in order to find out their contact relationship with the ultramafic body. A detailed cross section was completed starting in the south, 2 kilometers from the contact, up to the contact. The detailed structures of the exposed gneiss along a transect towards the contact between the host gneiss and ultramafic was studied. Additionally, pressure and temperature estimates on three samples along the transect has been conducted.