489 
Dr. Berger’s Account of the Isle of Man. 
occupied by these under the name of clay-slate, the general character 
being that of the Cornish killas. 
The gneiss near the Dun, passes into a chlorite slate very 
regularly stratified. The strata run north-east and south-west, 
dipping at a considerable angle to the south-east. A bed occurs 
here about twelve or fourteen feet wide, which lies between well 
defined strata, but is itself in a state of confusion. It appears to 
have once consisted of strata similar to those which enclose it, but 
which from some disturbing cause have been broken and bent in 
every direction at the time of their consolidation. A sketch 
(fig. 5, Plate 35.) of a portion of this ten feet in length, representing 
a vertical section formed by the stream at the Dun, will convey 
some idea of their disposition. It is much decomposed on the 
surface, having assumed a brown tinge to the depth of about one 
foot into the rock. A vein partly composed of clay, and partly of 
a steatitic substance united with a considerable portion of lime and 
a few specks of galena, traverses this. The bed may be traced 
from the road side a little beyond the bridge and along the course 
of the stream, about half way between the former spot and the sea, 
until it is lost there. Owing to the inclined position of the strata, 
connected with the rapid descent from the top of the hill to the sea 
shore, the real disposition of the bed has not a direction so nearly 
east and west, as the section formed at the surface might appear to 
indicate. It is from this bed lying conformably to the direction 
and dip of the laminae of clay-slate, that I presume the strata and 
fissile texture are in this spot coincident. The clay-slate on the 
western coast, between the northern termination of the red sandstone 
and Kirk Michael, does not assume that regularly slaty appearance 
which it presents on the opposite side of the island. There occur 
also in several places nodules of quartz sparingly dispersed, and 
3 q 2 
