GEOLOGICAL SOCIETY OF LONDON. 
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At Backbarrow, below Newby Bridge, tbe upper beds of this 
series are slaty, with a wavy cleavage dipping N.N.E. 80°, the 
beds dipping south-east 80^ ; these beds contain irregular calcare- 
ous nodules in great abundance, and Orthoceras articulatum was 
found in them. 
Mr. Sharpe refers to his former memoir for the description of 
the Windermere rocks on the east of the Lune, which extend to 
Greyrigg Forest, Whin Fell, and Howgill Fell ; in these Fells 
are several axes of elevation which require further examination. 
Ludlow Rocks: — These were described in the author^s former 
paper ; the area covered by them is larger than was there stated ; 
their lower boundary being now carried more to the north, and 
their eastern portion being extended in a sort of trough between 
the Lower Silurian slates of Shap Fell and the Windermere 
rocks of Whin Fell, crossing Barrowdale between High and Low 
Barrowbridge. 
In the lowest beds of the series in Fawcett Forest were found 
Lapicena lata and Turritella conicaj in a slaty rock. The Tere- 
hratula navicula is found thinly scattered throughout all the lower 
part of the formation, and occurs in vast numbers in a bed which 
forms about the middle of the Ludlow series. Mr. Murchison 
has told us that this little shell is usually found in such numbers 
as to form a bed which lies above the Aymestry limestone, and 
it serves to mark the place of that rock where it is wanting : and 
Mr. J. E. Davis informed the author, that at Stapleton near 
Presteign, where there is no Aymestry limestone, this species is 
found throughout the whole of the Lower Ludlow shales. Mr. 
Sharpe has made use of this shell in dividing the Upper from 
the Lower Ludlow rocks in Westmoreland, classing all the beds 
containing it in the lower series. The bed in which it occurs in 
greater abundance was traced through Underbarrow, by Tullith- 
waite Hall and High Cray, across the west end of Eather Heath 
and little south of Cowan Head, and also in Lambrigg Park , it 
is usually accompanied by Atrypa affinis/ Spirifer octoplicaius^ 
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