482 S. B. Medlicott—On Faults in Strata. 



formed ; and it would be rash in tlie extreme to come to any conclu- 

 sion on the point without a close search for collateral evidence. 

 Prof. Haughton has himself courageously given us an example of 

 how to work his system independently, and to apply his rule of pre- 

 ferring one hypothesis to many. In a recent paper (Journ, Eoyal 

 Geol. Soc, Ireland, vol. ii., p. 163, 1868-9) he takes up the lines 

 of elevation described by Mr. Hull in the Carboniferous rocks of 

 Lancashire (Quart. Journ. G-eol. Soc. Lond., April, 1868) as forming a 

 simple illustration of his system of Primary Conjugate and Secondary 

 joints — "an easy consequence of the same system of forces acting 

 upon that district, and by no means necessitating the hypothesis of 

 distinct sets of forces for each system of faults or axes." The 

 system of forces that produced the Lancashire axes acted in a north 

 and south direction, causing first the Pendle or Primary axis of 

 elevation ; secondly, the Pennine, or conjugate axis of elevation ; 

 and, lastly, the lines of fracture or Post-jurassic system of joints. 

 Thus the observed geological order of occurrence of these systems, 

 determined by Mr. Hull, coincides with the order that might have 

 been predicted from the action of mechanical forces." 



Now, a brief reference to another paper of Mr. Hull's (Quart. Journ. 

 Geol. Soc, Lond., 1864, vol. xx., p. 242,) describing the Pennine 

 range, will show that the north and south joints in that range 

 are only subordinate features in a great system of flexure, which 

 would, according to the universal practice of geologists, and accord- 

 ing to the rule used by Professor Haughton himself in his paper on 

 Waterford, be referred to the action of an east and west system of 

 forces, and perfectly inexplicable by a north and south force. 



I can only repeat my caution against the too rational as well as 

 against the irrational use of systems. 



While thus freely criticizing Dr. Haughton's work, I do so with 

 misgivings. My respect for his intellect and for the powerful in- 

 strument he is master of, is so great, that I am quite prepared to be 

 demonstrated in error. However, having studied his papers with all 

 the light that is in me, I feel pretty sure that a large majority of 

 geologists would take the view I have taken ; and I am willing to be 

 victimized, that we may all learn.^ 



11, Hastings Street, Calcutta, 30 July, 1870. 



* In Mr. Medlicott's former article on "Faults in Strata," the following errata 

 escaped correction (see Geol. Mag., toI. VI., 1869). Page 341, line 13 from commence- 

 ment of article, for 'experimental' read experienced ; second line from foot of same 

 page, for 'implicit' read explicit. Page 342, line 21 from foot of page, for 'having' 

 read leaving ; line 20 from foot same page, for ' instance' read evidence. Page 343, 

 line 3 fr'om foot of page, for ' lose' read hox (" box the compass") ; last line same page, 

 dele 'such.' Page 344, line 10 from top of page, for ' marks' read modes. Page 345, 

 line 26 from foot of page, for 'equivalents' read equivalence ; same page, line 7 from 

 foot, for 'run' read seen; same page, line 5 from foot of page, for 'their' read thin. 

 In justice to the ' Eeader,' we beg to explain that the Author's MS. of this article 

 (in 1869) was in a handwriting exceedingly dificidt to read. It is always desirable 

 that illegible articles should be recopied before they are sent to the printer, as it saves 

 numerous errors. This is especially the case where the author, from his residence 

 abroad, is unable to read and correct his own proof sheets. — Edit. Geol. Mag. 



