xlvi PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



sandstones and conglomerates to have been once far more extensive 

 than it now is. 



The details given by Mr. Ormerod respecting the occurrence of 

 the brine and rock-salt are not only valuable as regards geological 

 information, but important practically, as he touches upon many 

 points which cannot fail to aid those who may be seeking for brine 

 and salt in that district. 



It may be scarcely needful to remind you that the beds containing 

 the salt and brine (the latter merely a solution of the former, by 

 means of the water percolating amid the saliferous beds in those upper 

 marls of the new red sandstone series of the central portion of En- 

 gland,) are referred to a series of deposits known in Germany as the 

 Keupei' ; a term employed by Mr. Ormerod in his descriptions of 

 these beds. The salt would appear to be distributed in flattened 

 portions of irregular figures, and disseminated through certain beds. 

 As might be expected, sinkings of the upper ground take place when 

 the brine-springs have removed the salt in situations sufficiently near 

 the surface for this effect to be produced. 



At Northwich the upper bed of salt is considered to vary in thick- 

 ness from 84 to 90 feet, thinning off to the south-west, and losing 15 

 feet of thickness in about a mile. Its upper surface is uneven, pre- 

 senting cones and irregular figures. Beneath this bed is one of indu- 

 rated clay, traversed by veins of salt, and 30 feet thick. Under this 

 comes the second or great bed of salt, for the depth of 60 to 7^ feet 

 containing a considerable admixture of earth, so that this portion is 

 not worked. The next 12 or 15 feet is more pure, and the salt is 

 extracted from it. Beneath the earthy admixture becomes so consi- 

 derable, that, like the upper portion, it is unworked. At a pit at 

 Marston, northward from Northwich, the second bed of salt was sunk 

 through, and found to be there 96 feet thick. In other places it was 

 not passed through after sinking 117 feet. 



Mr. Ormerod estimates the thickness of the gypsiferous and sali- 

 ferous beds at Northwich and jNIiddlewich at more than 700 feet. 

 The strata technically termed water-stone beds, supporting these, he 

 considers to be 400 feet thick, and others beneath, to which he applies 

 the name Bunter sandstein, from their supposed identity in geolo- 

 gical position with the beds so termed in Germany, at 600 feet ; thus 

 giving 1 700 feet for the total thickness of the new red sandstone 

 accumulations of Cheshire, one which Mr. Ormerod nevertheless con- 

 siders as far below the real depth. 



From the care taken by Mr. Ormerod, his paper becomes a valua- 

 ble addition to our knowledge of the upper parts of that remarkable 

 accumulation of beds, a group of much interest, to which the English 

 geologists have given the name New Red Sandstone. With regard 

 to the saline character of its upper part, as shown in the district de- 

 scribed by Mr. Ormerod, you are aware that many hypotheses have 

 been brought forward to account for the occurrence of rock-salt amid 

 rocks of this and other geological periods. No doubt we should not 

 limit ourselves to one view of the mode of occurrence of salt and beds 

 highly impregnated with saline matter, when several explanations 



