On Dislocations of Rocks between Leven and Duddon Sands. 157 



labours of many past years by Mr. Bolton of Ulverston. It was 

 evident almost at a glance that the fossils he had collected from the 

 slate-rocks between Ulverston and Duddon Sands belonged to the 

 upper part of the Coniston group (No. 3). He kindly pointed out 

 to them some of his best localities, and they left the country con- 

 vinced that nearly all the older rocks between Ulverston and the 

 Duddon estuary belonged to the Coniston group, and consequently 

 that these rocks were not superior, but inferior to the Coniston grits, 

 though the prevailing dip and the geographical position of the groups 

 might seem to indicate the very contrary. 



In 1857 they again visited the district, re-examined Mr. Bolton's 

 unrivalled local collection, and again during two days made traverses 

 under his guidance. They then devoted a few days to the approxi- 

 mate determination of the vast breaks and faults, which have so much 

 disturbed the normal position of the physical groups in a part of 

 Furness, and made the colours of the Geological Map to appear 

 almost incredibly anomalous. 



The author then described, by help of plans and sections, the 

 faults above alluded to. 1. Black Coomb, protruded as it is at the 

 south-west end of Cumberland, seems to have been a kind of centre 

 of disturbance. The chloritic slates and Coniston group which 

 skirt the south-east side of Black Coomb have been ripped up by a 

 north and south fault which at one cast throws the Coniston lime- 

 stone about three miles to the south of its previous range. 



2. Similar enormous up-casts towards the south-east cause the re- 

 petition of the Coniston limestone and flagstone on the other side 

 of the Duddon Sands. This repetition is not produced by undula- 

 tions, but by great tcp-cast faults. 



3. A great east and west fault descends near the rivulet of Beck 

 Side with a down-cast to the north, which brings the Ireleth slates 

 down to the level of the sea at Sandside. 



4. A complicated fault, or system of faults, with a ver}' great up' 

 cast to the south-east, runs from Kirkby Hall, skirting the brow of 

 the hill under the great Ireleth slate quarries. The slates of Ireleth 

 cannot be separated from the Coniston flag. They do not overlie 

 the Coniston grits (as the author and other observers had long sup- 

 posed), but abut against them. This conclusion seems inevitable, 

 though the sections are broken and difiicult of interpretation. 



5. By a complication of faults the Coniston grits are widely ex- 

 panded in the hills immediately north of the great Ireleth slate quar- 

 ries ; but all the above mentioned groups are by an east and west 

 fault (or series of faults), with an enormous up-cast towards the 

 south, cut ofl^ from the normal groups (viz. Nos. 4, 5, 6, and 7 of 

 the typical section), which range towards Coniston water and thence 

 into Westmoreland. This east and west fault runs down into the 

 valley of the Crake, not far from Lowick Bridge. 



G. Another great fault ap{)ears to descend from Coniston water- 

 head down the Crake, producing an ujj-cast on its south-east side. 



The facts given in the above abstract necessitate a partial change 

 of nomenclature, 'i'iie Ireleth slates can no longer be appealed to 

 as groups suverior to the Coniston grita and on the parallel of the 



