W. T. Blanford — Oil Faults in Strata. 115 



But tlio above troo-liko form was not the whole of the discovery. 

 Imbedded likewise in the ironstone, and occurring for the most part 

 near the walls of the place, and low down, were numerous twig-(?) 

 like remains. These are of a harder nature than the trunk mass — 

 they are in better preservation — and in some specimens exhibit 

 beautiful minute striation, with what seem to me to bo little scars 

 arranged in a uniform pattern. They are well worth collecting, 

 are not very scarce, and the miner's hammer will bring out good 

 examples. 



The cleft, whence all that was of interest has long been removed, 

 is now partially filled with mining refuse and rock debris. In the 

 eastern end of it a shaft was sunk upwards of forty feet further, 

 passing through decomposed limestone containing one bed of ore. 

 From the shaft, adits have been driven beneath the floor into sound 

 limestone generally, with here and there decomposed portions tinged 

 with the mineral. The marketable product, associated with the 

 fossils, was the soft red oxide, found in layers of from one to seven or 

 eight inches thick between the hard beds of ironstone, several 

 hundred tons of which had been gained. Lamination is sometimes 

 finely shown in blocks from the hard beds, and cleavage-planes, at 

 right angles to the bedding, set with glittering crystals of iron- 

 stained quartz. 



Narrow fissures in the limestones near, open to the drift, have 

 revealed other curious forms of haematite, but whether they also are 

 of vegetable origin, I am unable to say. Their chief peculiarity is 

 a kind of foliation, ascribed by some observers to heat, but which I 

 would suppose might be the result of great pressure : they are 

 unlike any varieties I have ever seen in Furness.' 



V. — On Faults in Strata. 



By W. T. Blanfokd, A.E.SJtf., F.G.S. 



Tl TY friend and colleague, Mr. H. B. Medlicott, published, in the 

 jJjL August (1869) number of the Geological Magazine, a paper 

 " On Faults in Strata," in which he endeavoured to show that the 

 evidence usually accepted for faults, in the true geological accep- 

 tation of the term, is insufficient ; that a large number of the 

 lines of junction between rocks of dissimilar age, usually mapped 

 by the Survey of Great Britain and other Surveys as " faults," are, 

 in truth, natural junctions, due to deposition against cliffs or other 

 steep surfaces ; and that direct evidence of friction is necessary to 

 establish the existence of a fault. The latter is rather left to be 

 inferred than positively asserted ; nevertheless it is very clearly 

 intimated that it is the writer's opinion. 



I have expected in vain that some member of the Geological 

 Survey of Great Britain would have defended the system of mapping 

 adopted in that Survey, but hitherto no one has replied to Mr. 



* Two articles on the subject appeared in The Grange Visitor — a weekly newspaper 

 for 1868, D. Atkinson, printer, Ulverstone— by Mr. J. P. Morris and Mr. Samuel Salt. 



