GEOLOGY 



fore Lower Coal-Measures, including the Kilburn coal and all the 

 Measures in the Ruddington boring. 



The Upper Series have been recognized by Mr. Walcot Gibson l 

 in the cores from the boring at Thurgarton above the ordinary Middle 

 Measures, by their resemblance in character and succession to those of 

 north Staffordshire, which he names in ascending order the Etruria 

 Marls, the Newcastle-under-Lyme Series and the Kee/e Series. At Gedling 

 a Lower Series, containing sphsrosiderites, called the Black Band Series, 

 has also been recognized in a diminished form. 2 Mr. Gibson also 

 quotes the ferns Neuropteris rarinervis and Pecopteris miltoni, with Spheno- 

 phyllum and Cordaites as obtained in the uppermost beds in both counties, 

 though these are members also of the Middle Measures flora. The 

 relations of these beds to any definite coal seam of the Middle Series, 

 which was not ascertained at Thurgarton, is shown in the Gedling 

 shaft, where beneath 93 feet of red strata referred to the Etruria Marls 

 are found 762 feet of ordinary Measures above the Top Hard coal. 

 This thickness, if there is no error, is much less than that found at 

 Shireoaks (1,050 feet) or Southcar (1,364 feet) between the Top Hard 

 and the Rotherham Red Rock which lies below the shales called Upper 

 Coal-Measures in Yorkshire. If this portion of the series thins south- 

 ward some of the 1,0001,300 feet of Measures which at Bestwood, 

 Linby and Annesley overlie the Top Hard may be expected to belong 

 to the Upper Series, and in fact their resemblance at Bestwood to the 

 beds at Scarle has been recognized. 3 Now Professor Hull 3 also recognized 

 the resemblance of the red shales at Scarle to the Upper Coal-Measures 

 of north Staffordshire, and Professor Green 4 is said also to have recognized 

 the Measures above the Rotherham Red Rock at Southcar as the same 

 as at Scarle. This would seem to suggest that the Rotherham Red Rock 

 might be taken to be the local base of the Upper Series 5 in the northern 

 part of the county. 



The Coal-Measures have, of course, greatly changed their position 

 since they were laid down. Part of this change must have taken place 

 while the deposition of the series was still going on. Beds of coal with 

 their swampy seat earth and their fern-filled roofs must have been 

 originally formed near the sea level. If therefore the Kilburn coal near 

 the base and the Manor coal near the top of the series were deposited at 

 different times at approximately the same level there must have occurred, 

 between the two dates of their deposit, a sinkage of the ground of 2,700 

 feet. When room had thus been made for the Upper Measures and the 

 last of them had been deposited, the Carboniferous period ceased, and 

 there was a long interval before the next succeeding period of deposition 

 commenced. 



During this interval the Pennine range was formed and the strata 

 on the east side obtained a dip to the east and were raised towards the 



1 >uart. Journ. Geol. Sac. vol. Ivii. a See 'Summary of Progress in 1902.' 



3 See PitK. I nit. Civ, Eng. xlix. 159-68. * See Dunstan, loc. cit. 



5 Sec Geol. Survey Mem. sheet 83. 

 II 



