239 
ON A BASE TO THE CARBONIFEROUS ROCKS IN TEESDALE. 
BY J. R. DAKYNS, ESQ., M.A., OF II. M. GEOLOGICAL SURVEY. (PL. IX.) 
I PAID a visit early in November, 1876, to Teesdale, where 
I saw certain sections, the bearing of which is not generally 
known to Geologists. The part of Teesdale I refer to is that 
above the High Force. I may premise that this part of the 
dale is in the heart of the Carboniferous area ; Fells composed 
of Carboniferous rocks rise on all sides ; and I never heard 
it suggested that any other than Carboniferous beds were to 
be found in any part of the dale, with the exception, of 
course, of intrusive rocks ; but this suggestion I am about to 
make, or rather have already made. 
The sections I wish to call attention to are two ; one at the 
foot of the Falcon Glints, and the other on the bank of the 
Tees at the Old Pencil Mill below Cronkley, and about a 
couple of miles below the section at Falcon Clints. (Plate ix.) 
The section at Falcon Clints has, I believe, been described 
by Sedgwick. It is on this wise : The precipitous crag 
called Falcon Clints is formed by the Whin Sill ; imme- 
diately beneath the Whin is a bed of Limestone (one of the 
Carboniferous beds) highly altered into a sugary crystalline 
rock ; below the Limestone we have what seemed to be alter- 
nations of Shale and Sandy beds and Limestone, all more or 
less altered ; and at the very foot of the bank, j ust above the 
alluvium, is seen about a foot of peculiar Breccia. This Breccia, 
of which I have sent a few small hand specimens to Professor 
Green, reminds me of the basement bed of the Carboniferous 
series as seen in Hibblesdale and Chapel Dale, above Ingleton. 
As all the beds between the Breccia and the Whin arc more 
or less altered, I should suppose that the Breccia is itself 
altered ; and it is jDossibly owing to this alteration, induced by 
the Whin above, tliat the round pieces of quartz owe their 
