116 MR. .T. MORRISON OX [vol. lxxiv 



5. The Shap Minor Intrusions. By James Mobrtson, B.A., 

 B.Sc. (Bead November 21st, 1917. Communicated by 

 Dr. Herbert Lapworth, M.Inst.C.E., Sec.G.S.) 



[Plate XIII.] 



Contents. 



Page 

 I Introduction 116 



II. Previous Work 117 



III. General Remarks on the Intrusions 118 



IV. The Acid Intrusives 120 



V. The Intermediate Intrusives 125 



(a) The Potter-Fell Type. 



(b) The Mixed Series. 



VI. Age and Order of the Intrusions 137 



VII. Summary 141 



I. Introduction. 



An investigation on the minor igneous intrusions of the south-- 

 eastern part of the Lake District was commenced b}' the writer in 

 1913, the Shap area being first selected for stud}'. The results 

 of the work in that neighbourhood were such as to indicate the 

 desirability of extending the investigation into the adjoining 

 areas on the east and north. The work has not vet been com- 

 pleted, prevalent conditions having considerably interfered with its 

 progress. It is perhaps advisable, therefore, to place on record the 

 results so far obtained, leaving the remainder to be dealt with on 

 some future occasion. 



The Shap granite has long been of interest to geologists, its 

 marked porphyritic character and conspicuous basic segregations 

 having quite early attracted attention. Little, however, of any 

 moment concerning it was published before 1868, when H. A. 

 Nicholson's paper ' On the Granite of Shap in Westmorland ' 

 appeared. 1 This was followed in 1875 by a series of papers by 

 J . Clifton Ward on the granitic rocks of the Lake District, in one 

 of which 2 their origin was discussed, the work of Sorbv being 

 taken as a basis. 



It was not, however, until 1891 that the results of a detailed 

 investigation by Dr. Harker & Prof. Marr on the granite and its 

 associated rocks appeared in the Quarterly Journal of this Society — 

 a comprehensive study, both of the granite itself and of the 

 effect produced on the surrounding rocks by its intrusion. 



While the plutonic mass has thus received the attention that it 



1 Trans. Edin. Geol. Soc. vol. i (1868) p. 133. 

 8 Q.J. G. S. vol. xxxi (1875) p 590. 



