XX. Remarks on Farey's Account of the Stratification of the Limestone District of Derbyshire

Philosophical Magazine Series 3 ISSN: 1941-5966 (Print) 1941-5974 (Online) Journal homepage: http://www.tandfonline.com/loi/tphm14 XX. Remarks on Farey's Account of the stratification of the limestone district of derbyshire W. Hopkins Esq. M.A. To cite this article: W. Hopkins Esq. M.A. (1834) XX. Remarks on Farey's Account of the stratification of the limestone district of derbyshire , Philosophical Magazine Series 3, 5:26, 121-131, DOI: 10.1080/14786443408648421 To link to this article: http://dx.doi.org/10.1080/14786443408648421 Published online: 01 Jun 2009. Submit your article to this journal Article views: 2 View related articles Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=3phm20 Download by: [University of California Santa Barbara] Date: 16 June 2016, At: 05:44 Mr. Hopkins on the Stratification of Derb~yshire. l°1 and inclosing a firm and longitudinal fibre, or rather a hun- dle of longitudinal fibres united into one cord, like the fila- ments that compose the nerves of animals, and which termi- nate uhimately in soft, bibulous, and club-shaped appendages designated by the appellation of spongiolce. Thus we trace in plants the foundation of three grand orders, depending upon the relative simplicity or complexity of the structure of the caudex~ anti presumed to exhaust the subject. They agree in point of number, but not in point of specific extent, with the arrangements of modern botanists, by which plants are reduced to three grand orders depending upon tlle structure of their seeds--the aeotyledonous, the monocoty- ledonous, and the dicotyledonous. Whether or not these groupings of threes give ally support to Professor Burnett's system of triads, I am not able to say ; but what we learn, unequivocally, from the foregoing investigation is, that the decomposite organs of all plants, to whatever division be- longing, are reducible to one or other of the tbllowing con- stituent parts~epidermis, pulp, pith, cortical layers, ligneous layers, fibre~to the analysis of which we now proceed. [To be continued.] XX. tlemarks on Farey's Account of the Stratification of the Limestone District of Derb#shire. B.y W. HoPKIns, Esq., M. A., Mathematical Lecturer of St.Peter' s College, Ca mbridge, and Fellow of the Geological and Cambridge Philosophical Societies. To the Editors of the Philosophical Magazine and Journal Gentlemen, ~/I R. CONYBEAI~E,, in the latter part of his "Inquiry how far De Beaumont s theory is applicable to the mountain chains of this country," which appeared in the Number of the Ptlilosophical Magazine for June, in speaking of the elevated chain of hills which ranges N. and S. through our northern counties, has expressed considerable doubts as to the accuracy of Farey's account of the geology of the limestone district of Derbyshire, which forms the southern extremity of the chain ; Downloaded by [University of California Santa Barbara] at 05:44 16 June 2016 and this I observe has led you to refer, in a note, to an abs- tract, published in the Phil. Mag. fbr January, of an account which I laid before the Cambridge Philosophical Society of an investigation I had recently made of one or two important points in the stratification of that county. During the spring of tile present year I have had an opportunity of extending my investigation over the greater part of the district; and as 7hirdSeries. Vol. 5. No. 26. A~. 1834. R 122 Mr. Hopkins's Remarks on Farey's Account of the I have now so fully satisfied myself of the entire erroneousness of Farey's views of its stratification, I will, with your permis- sion, enter with some detail into a refutation of them. Before I notice those points on which Farey and myself differ so widely, I will mention one in which we are entirely agreed, viz. the regular interstratification of the toadstone with the limestone. The direct evidence of this is aftbrded by those cliffs in which the faef is matter of observation; and the indirect evidence of it must be sought in tile circumstance of our being able to found on this hypothesis a generalization which shall clearly and distinctly embrace all the particular phaznomena which the stratification of the district presents to us. The validity of this latter evidence must, of course, de- pend on that which can be offered in proof of the generalization contended for; but as the examination of this evidence would necessarily involve the complete discussion of the subject, into which it is far from my intention to enter at present, I must content myself with stating my conviction of the fact of this interstratification of the toadstone. Any opinion of its uneonformability with the limestone beds, professing to rely upon observation, can only, I think, be founded on a superficial examination or on an imperfect conception of the subject. I mention my conviction on this point more particularly in conse- quence of Mr. Conybeare's having suggested, in the paper above alluded to, the possible unconformability of the toadstone, from its having, perhaps, been thrust up among the limestone beds at a period posterior to their formation. In addition, however, to the reasons above mentioned, I conceive that any such idea must be completely negatived by the total absence of all indications of that mechanical violence which must necessarily attend the forcible intrusion of a mass of ig- neous rock among masses previously deposited. ] will proceed, however, to the exposition of what I con- eeive to be erroneous in Farey's account of the district. He has asserted (and it should be recollected that on this subject he has made many assertions, but has given no proofs,) that there exist in the limestone district of Derbyshire three distinct beds oftoadstone. The limestone occupying the surface, and lying above the frst or highest toadstone--that Downloaded by [University of California Santa Barbara] at 05:44 16 June 2016 between the first and second toadstones--that between the second and third--and that beneath the third--he has termed respectively the3grst, second, third, and fourth limestones. He states that these beds of toadstone have continuous bassets, that of the third or lowest bed commencing on the north near Casfleton, and ranging by ~Vormhill, Chalmerton, Pike Hall, and tile Grange to Bonsai Dale; and those of the two other Stratification of lhe Limestone District olDer@shire. 12.~ beds ranging nearly parallel to the above basset at short di- stances to the west of it. Let us first consider the two latter bassets, i. e. those of his first and second toadstones. He asserts that they commence on the north at the great fault (which he assumes to run N. and S. between Castleton and Litton,) not far from Wind- mill Houses, the first passing near the village of Litton and the second near Tideswell. Now of the existence of a toadstone basset anywhere to the north of Litton, where these are said to commence, I have not been able to find the most remote indication, either in my own examination of the spot, or in the information I have derived from the most intelligent miners in the neighbourhood; and moreover I can myself" bear positive testimony to the fact that the toadstone near Tideswell, which Farey asserts to belong to the second bed, belongs to the same as that at Litton, which he has assigned to the first, for I have most distinctly traced the toadstone without the smallest interruption from the one place to the other. It is manifestly brought up by the E. and W. fault which has elevated Litton Edge. Again, (if I understand him rightly, which is sometimes no easv matter~ even with the aid of his able commentator*,) Farey says, that the first basset passes nearly at the southern extremity of Crossbrook Dale, and from thence to Fin Copt Hill; and that the second passes fi'om near Tideswell to the southern extremity of Tideswell Dale next the Wye, ranging thence easterly along the sides of Miller's Dale and Monsal Dale till it descends to the level of the river Wye, at the mouth of Crossbrook Dale, and that crossing the river at that point, it returns westerly along the opposite side of the valley to the top of Priestcliff Lowe. Now, in the first place, I deny the possibility of tracing any continuous basset from Litton to the south end of Crossbrook Dale, or from the point where the toadstone appears north of Tideswell to the southern extremity of Tideswell Dale; nor is there the slightest indication in either case of any faults by which the bassets between those places respectively might be hidden. In the second place, the toadstone which appears in the southern part of Crossbrook Dale is not the western ex- Downloaded by [University of California Santa Barbara] at 05:44 16 June 2016 tremity or basset of the bed to which it belongs, for nothing can be more manifest than that the bed passes across the dale, of which for some distance it occupies the whole of the lower part, ascending in exactly a similar manner on both 6 See "Geology of England and Wales," in which Mr. Conybeare has given an exposition of Farey's views far more intelligible than that which Farey himself has given of them. R2 124 Mr. Hopkins's Remarks on Farey's Account of the sides of it to the height (where the upper surface of tile bed is most elevated,) of perhaps 200 feet. It has manifestly been raised to this position by an E.

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