XXX. a Sketch of the Natural History of the Cheshire Rock-Salt District

Philosophical Magazine Series 1 ISSN: 1941-5796 (Print) 1941-580X (Online) Journal homepage: http://www.tandfonline.com/loi/tphm12 XXX. A sketch of the natural history of the Cheshire rock-salt district Henry Holland Esq. To cite this article: Henry Holland Esq. (1812) XXX. A sketch of the natural history of the Cheshire rock-salt district , Philosophical Magazine Series 1, 39:167, 210-215, DOI: 10.1080/14786441208638112 To link to this article: http://dx.doi.org/10.1080/14786441208638112 Published online: 27 Jul 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=tphm12 Download by: [University of Toronto Libraries] Date: 04 June 2016, At: 23:23 ~10 .,4 Sketch of the Natural HMory of being in the focus to which the other radiates, it must f~t- cititate the escape of caloric from the other, by quickly ab- sorbing all that is sent to it by radiation from that other body. In the common experiment the thermometer is the radiating body, and the ice the absorbent. A.T. XXX. ,4 Sketch of the Natural History of the Cheshire Rock-Salt District. By HENav HOLLAI~D, Esq. Ho- norary Member of" the Geological Society *¢. THE vast beds of fossil or rock-salt, which are found in different parts of the county of Chester, thrill undoubtedly the most important and peculiar feature in the mineralogy of this district. In offering to the notice of the Geologic-a] Society some remarks upon these mines, it may be proper to premise, that in a Survey of Cheshire, which I had the honour of drawing up for the Board of Agriculture, I en- tered at considerable length upon the subject of their natural history,-and upon the manufacture of white salt froru the brine springs to which they give rise. It will be my present object to consider more especially the mineralogical situation and characters of the Cheshire rock-salt; and though the repetition of some statements must necessarily occur ; this, in the case of a work only partially known, can, I conceive, be attended with little disadvantage. Character of the Country surrounding the Salt Mines. In speaking of the general situation of the Cheshire salt mines, it will be proper to state some facts with respect to the nature of the surrounding country, timt their mineralogical relations may more clearly be understood, and an op- portunity given to speculate upon the probable origin of these important strata. The southern parts of Lancashire, the northerfi extremity of Shropshire, and the whole of the intervening county o~" Cheshire, form in conjunction one vast tract of plain country, interrupted by few elevations, Downloaded by [University of Toronto Libraries] at 23:23 04 June 2016 and these inconsiderable in size and extent. The area of this plain may be regarded as extending nearly fifty miles from north to south, and as having an average breadth of twenty-five or thirty miles. Its eastern boundary, as more immediately regards the county of Chester, is a high range of sandstone hills, stretching from north to south along the borders of Derbyshire and Staffordshire ; eonnected on t lrrom the Transactions of the Geo!oglcal Society, vol. i. the the Cheshire Rock-Salt District. ~11 the north with the hills in the West Riding of York, and on their eastern side passing into the limestone hills of Derbyshire. The sandstone, in a considerable part of this range, is shity in its structure, and would seem to belong to the Independent Coal-formation of Werner, some pretty extensive beds of coal being fotind and worked under it, The southern boundary of the plain., which is the one ap- proaching most nearly to the rock-salt, is irregularly formed by ridges of limestone and ealeareous sandstone, leaving open some eommunication~ with the level country in the middle of Shropshire. To the west its limits are marked by the sandstone and limestone hills in the adjoining part of Wales, and by tile sandy ~estuaries of the Mersey and Dee. The only ridge of hills, properly speaking, within the Cheshire plain ~, is one on the western side of the country, extending with a few interrnptions from Frodsham to Mal- pas, and including in its progress from north to south, the hlgh. grounds of Delamere. .F°rest' the Hill. of Beeston, and the Peekforton Hills. This range, which no where attains an elevation of more than four or five hundred feel, is com. posed entirely of sandstone. A small quantity of copper ore has been found in the Peekforton Hills, which form its south.era extremity. Another ridge of land, possessing a small and irregular elevation above the adjoining plain, may be traced from the hills on the eastern border of Cheshire, in a westerly or north-westerly direction to Hahon and RuneQrn. ~xt this point, where it attains iis greatest height, it is separated from the northern extremity of the former ridge, only by the intervention of the valley of thg Weaver, whieh valley is here about ~wo miles iii width. Towards the eastern extremity of this range~ we meet with a singular sandstone hill, called Alderley Edge, in which have been found ores of lead, copper and cobal b and masses of sulphate of barytes. This distribution of the high grounds in the Cheshire plain is traced out in the annexed map, and it will be seen, Downloaded by [University of Toronto Libraries] at 23:23 04 June 2016 by a reference to thi% that they tbrm three distinct divisions ot" its area: one to the west of the higher sandstone range another to the east of this~ and south of the lower range ; and a third lying north of the latter, and including the southern parts ef Lancashire. With the exception of a very few instances only, the existence of the rock-salt" ap- pears to be exclusively confined to the southern or central plain. 0 ~ Yh¢ ~1~ .,4 Sketch of the _Natural History of The marl beds form the most peculiar feature in the aT- luvial strata of the Cheshire plain. These occur in great abundance in every part of the district; being found not only under the common soil, but occasionally, as on the borders of Delamere Forest, interposed between layers of sandstone rock. The Cheshire marls are also very fre- quently met with in iarge detached masses, twenty or thirty feet in thiekness,.in the working out of which, it is not unusual to find large assemb!ages of fragments of the older rocks. Portions of granite, otten of large size, and show- ing on their surface evident marks of attrition, are among the most common appearances in these collections: no granitic rocks are found within fifty or sixty miles of this district. The divisions which I have pointed out in the Cheshire plain are still further marked by the course of the stream~ in this tract of country. The Dee is the great river of the western plain ~ the Weaver and its subordinate streams re- ceive all the waters of the southenl division; while the Mersey and its tributaries do the same in the northern por- tion. From their local relation to the great beds of rock- salt, the streams of the southern or central plain possess a peculiar importance. The Weaver rises in the Peekforton Hills, near the Shropshire border, runs for some miles towards the south- east, then making a sudden flexion to the north, continues in this direction, by Nantwich and Winsford, to North- wich~ about thirty miles further. Here it takes a north- westerly course to Frodsham, where it expands into a sandy ~estuary~ connected with the channel of the Mersey. l't receives its principal accessions at Northwich, where it is joined by the united streams of the Dane and Weeloek fi'om the south-east, and by a stream called Witton Brook from the east. At Anderton, a little below Northwich, the valley~which has hitherto been comparatively wide and fiat, is suddenly contracted by the approach of two ranges of' high ground; that on the western side of the river con- Downloaded by [University of Toronto Libraries] at 23:23 04 June 2016 necting itself by a .gradual rise with the heights of Delamere Forest j the opposite one passing by a series of irregular elevations into the range of high land, which separates the southern from the northern plain. _At Frodsham the river flows, as I before mentioned, between the termination of this high ground and that of the ridge which crosses the county from north to south, the hills thus opposed cor- responding perfectly in appearatlce amt ~tructure. We have the Cheshire Rock-Salt District. ~13 have thus two distinct contractions in'the valley of the Weaver below Northwieh ; a circumstance in some degree worthy of notice. Situation of the Brine Springs, Rock-Salt Mines, &e. I have dwelt thus minutely upon local facts from their connection with the situation of the rock-salt, which, with few exceptions, has vet been ascertained to exist only in the valleys of the Weaver and its tributary streams ; in some places manifesting its presence by springs impregnated with salt ; itr other places being known by mines actually carried down into the substance of the strata. A refereoce to the map will show the several situations where brine sprin~s occur, or where mines have been sunk, in the course of tl~se valleys. Between the source of the Weaver and Nantwieh, it will be seen that many brine springs make their appearance ; and in the latter part of this course, it would seem that brine might be obtained by sinking to some depth in any place near the banks of the Weaver.

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