1853.] ORMEROD — PSEUDOMORPHOUS CRYSTALS OF SALT. 18/ 



4. On PsEUDOMORPHous Crystals q/" Chloride o/" Sodium. 

 By G. Wareing Ormerod, M.A., F.G.S. 



In a paper read before this Society, on 1st December 1852, by Mr. 

 Strickland, on Pseudomorphous Crystals of Chloride of Sodium in 

 Keuper Sandstone *, no reference is made to prior observations on 

 the same point. In my paper " On the Principal Geological Fea- 

 tures of the Salt-field of Cheshire f" it is stated that "the "Water- 

 stone beds (a subdivision of the Keuper) at Holmes Chapel have the 

 same peculiar crystal as those at Lymm, Preston on the Hill, and 

 elsewhere ;" and in a note it is added, "At this place the crystals are 

 of silicate of protoxide of iron. This seeming crystal is probably 

 caused by the component matter taking the places of scattered 

 crystals of Chloride of Sodium, the form of which both in Cheshire 

 and at Slime Road in Gloucestershire they have taken, exhibiting, if 

 so, the lowest traces of the salt." To Mr. Grace Calvert (Honorary 

 Professor of Chemistry at the Royal Manchester Institution) I was 

 indebted for the examination of this specimen, and to him any credit 

 for the discovery, as far as relates to Cheshire, is due, he having, on 

 my showing him the specimens, stated his opinion that the crystals 

 were Pseudomorphic Chloride of Sodium. I had omitted to ask his 

 permission to allow me to mention his name when my paper was 

 read, and it was therefore not then given. This paper was read before 

 the Geological Society 8th March 1848, when specimens were ex- 

 hibited and a discussion took place, when Professor Buckland men- 

 tioned many localities in which he had observed this pseudomorph, 

 for which he had not hitherto been able to account. 



In July 1850 the Government Reports of the Natural History of 

 the State of New York were sent over as a • donation to the Free 

 Library and Museum of the Borough of Salford, and shortly after- 

 wards, on examining the geological division of that work, I found 

 that the same peculiar crystal had been observed in the district lying 

 to the south of Lake Ontario. In Part 3, pages 102 and 103, 

 Mr. Lardner Vanuxem notices them thus : " Hopper-shaped cavities, 

 Onondaga Salt Group. These forms and cavities are of great im- 

 portance, for they were produced by common salt, no other common 

 soluble mineral presenting similar ones. They are found in the 

 gypseous shale or marl in its more solid and slaty parts." A drawing 

 is given of specimens (from Bull's Quarry, Town of Lenox, Madison 

 County) in which the pseudomorphs resemble those found in Cheshire 

 and Gloucestershire which have come under my notice. 



In Part 4, page 127, Mr. James Hall mentions that similar crystals 

 were found in Wayne and Monroe Counties, but that he had rarely 

 observed them in Genesee or Erie Counties, the most perfect which 

 he had seen being at Garbutt's Mill on Allen's Creek, Part 3 was 

 published in 1842, and Part 4 in 1843. 



In making these observations, I must not be understood as in 

 any way attempting to take from Mr. Strickland the credit of a dis- 



* Quart. Journ. Geol. Soc. vol. ix. p. 5. 

 t Quart. Joiirn. Geol. Soc. vol. iv. p. 273. 

 VOL. IX. PART I. O 



