105 
at the cliffs near Port St. Mary, and on the eastern side of 
Langness the general dip is from 30° to 40° E. of S. at a high 
angle. From these dips it is evident that a well-marked 
anticline exists in these rocks. Several years ago Professors 
Harkness and Nicholson pointed out that this axial line runs 
from Port Erin to Port Moar, near Maughold Head. The 
grey slaty shales and flags which occur on both sides of the 
great anticline were considered by them to be the equivalents 
of the Skiddaw slates of Cumberland. They based this 
conclusion partly on the lithological resemblance, partly on 
the fact that the beds in the two localities are in the same 
line of strike, and also on the discovery of Palceochorda 
major, a fossil very abundant in the Skiddaw slates of 
Cumberland. 
“At Douglas Head, and northward as far as Clay Head, 
they found certain green slates and porphyries which they 
considered to be on the same horizon as the green slates and 
ash beds of the Lake country. 
“If this correlation be correct, as all the available evidence 
seems to prove, then it follows that the grey slaty shales and 
flags of the Isle of Man are of Lower Llandeilo age. They 
are inferior in position to the Silurian rocks of the south of 
Scotland. Lithologically they are totally different from any 
part of that series. The green slates amd porphyries are in 
all probability of Lower Caradoc age. In this locality there 
seems to be no break between the two series, for they rest 
conformably on the grey slaty shales and flags.” 
So far as I have observed, these schists consist chiefly of 
argillaceous and arenaceous shales, generally of a brown but 
sometimes of a bluish and occasionally of a greenish colour. 
Beds of ash are met with in them, but they afford very few 
calcareous bands. For the most part they appear to have 
been elevated to the high angle at which they are now 
found by the raising up of the central chain of hills running 
