<p> Five pyroclastic breccia rock samples from a felsic volcanic sequence at Kakagi Lake, Northwestern Ontario, have been analysed for eight major elements using X-Ray Fluorescence to study the fragment-matrix relationships. The salic fragments represent a rhyodacitic composition and the matrices are of andesitic composition showing Fe and Mg enrichment and Si deficiency compared to the fragment. </p> <p> Four matrix and four fragment samples were obtained from one rock,and a triplicate analysis of one of these matrices,compared to the average of the four matrices, showed that the variability of the composition throughout the rock was not due to the analytical procedure. </p> <p> These results agree reasonably well with the trends found in previous work by Goodwin (1968) and Baragar and Goodwin (1969) considering the matrices only. The fragment-matrix study for this area is unique and has been carried out in conjunction with Smith (1971). </p> / Thesis / Bachelor of Science (BSc)