110 
THE COMPLEX OF IGNEOUS ROCKS AT OATLAND, S ANTON, 
ISLE OF MAN. 
BY FRANK W. WHITE. 
(Plates VIII.— XI). 
{Read Uh March, 1910.) 
INTRODIJCTION. 
The field relations of this complex of igneous rocks have 
been described by Mr. G. W. Lamplugh, F.R.S., in the Survey 
Memoir, " The Geology of the Isle of Man " (1903). Petrological 
notes by Prof. W. W. Watts, M.A., F.R.S. , are also included in 
the volume. 
A description of the acid type of rock at Oatland, as revealed 
by one thin section, had previously appeared under Mr. B. 
Hobson's name in Vol. XLVII. of the Q.J.G.S., and, later, in 
" Yn Liaor Manninagh " for 1892 (Vol. I., pt. 10). 
Dr. F. H. Hatch briefly refers to the occurrence in his " Text 
Book of Petrology " (1909), pp. 285-6. 
FIELD RELATIONSHIPS. 
This igneous complex near Santon, in the S.E. part of the 
Isle of Man, is intrusive into the thinly-bedded Lonan Flags of 
the Manx Slate series. The Flags are visible on the East, West, 
and South-East in the immediate neighbourhood of the igneous 
mass, and have there been altered by the intrusion to a baked 
and splintery character. They are minutely spotted and banded, 
and, under the microscope, appear to consist of fine clastic grains 
of quartz in an aggregate of fine flakes of mica set in a groundmass 
of chlorite. 
The structural axis of the Island runs N.E.-S.W. from 
Maughold Head east of Ramsey, through Foxdale to the CaK of 
