"Two basic xenoliths were taken from the Shap adamellite and two from the Glen Fyne porphyritic granodiorite. Each specimen was divided into the three parts; margin and core of the xenolith and the surrounding host rock. Porphyritic alkali feldspar and sphene were separated from each part and the rocks and minerals were analysed for trace elements and for Na and K. Four specimens of the assumed parent rocks of the xenoliths were also analysed. The results indicate that the two host rocks are similar in trace element content, that equilibrium between minerals in host rock and xenoliths extends to their trace element content and that late stage magmatic fractions may have played a part in the alteration of the xenoliths."