OF THE NOETH-WEST OF ENGLAND. 229 



of salmon coloured argillaceous shale of about thirty feet in 

 thickness, containing impressions of neuropteris cordata^ and 

 many other common coal-plants. Their position in the carbo- 

 ferous series is immediately above the Collyhurst sandstone, 

 and under all the coals which have as yet been worked in the 

 Manchester coal-field, say about 2,250 feet below the upper- 

 most of the carboniferous strata at Ardwick. Their dip is 1 0° 

 east-of-south, at an angle of 24°. This inclination is not the 

 usual one in the adjoining coal mines of Mr. Buckley, where 

 it is only 18° to the south-south-west, and must be attributed 

 to the fault which has thrown down the coal-measures at the 

 point of junction with the permian beds, and now forms the 

 trough in which the latter lie. In the collieries above 

 alluded to the coals on their strike abut against, or, as the 

 miners express it, are "cut off" by the permian beds. 



When the British Association visited Manchester in 1842, 

 an excavation was made to ascertain the state of the lower 

 new red sandstone and the coal-measures at their point of 

 contact. It was then found that the latter strata were mixed 

 with the loose sand of the former, and the coal-measures had 

 lost their original laminated structure and become homogeneous, 

 presenting almost the appearance of drift clay, so that the ab- 

 solute line of demarcation of one formation from the other 

 could not be determined with any degree of nicety; their 

 colour was a deep red, mottled with marks of a dirty yellow ; 

 in fact, their whole appearance, as well as the red and salmon 

 colours of the underlying strata, to a great depth, seemed to 

 shew that they had been long exposed to the action of water 

 before they were covered up by the lower new red sandstone. 



The dip of the two formations does not differ much, that 

 of the coal-measures being at an angle of 24° to a little east 

 of south, that of the lower new red sandstone 17° to the south- 

 west; while the usual dip of the former, the Manchester coal- 

 field, is 18° to south-south-west, the latter from 5° to 10° to 

 the south-west. The coal-measures were doubtless partly 



