GEOLOGY 



marked with rootlet scars. It is cut off above by the horizontal coal 

 seam, in which it appears lost, but on the other side of the seam the 

 stem corresponding to the root may sometimes be seen standing upright 

 above it. These roots are most abundant below the ' Top Hard' seam. 

 They have long been known in the Newcastle Colliery at Old Basford, 

 one being preserved in the museum at the University College, Notting- 

 ham, and some specially fine examples accompanied by the correspond- 

 ing stems have been described by Mr. Shipman from the same horizon 

 elsewhere. 1 In one of these, found at Bulwell, the stem belonged to 

 Sigillaria and had a diameter of 5 ft. 6 in. and a length preserved, now 

 filled in with sand, of 7 ft. 6 in. In another, found at Newstead, the 

 stem was Lepidodendron, and had a diameter of 9 feet and a length pre- 

 served of 7 feet. At a little higher level similar trees of smaller diameter, 

 3-4 feet, are found. Such trees can only be seen in the mines themselves, 

 as they are too large to bring up. 



The ironstone occurs in a peculiar form. It does not form a rock- 

 bed but consists of concretionary nodules hardened by compounds of 

 iron. These nodules occur in great numbers at various horizons and 

 often contain the remains of some organism embedded in them, such as 

 a bivalve shell or a fern. The bivalve shells, named Anthracosia? belong to 

 the family Unionida or ' freshwater mussels,' hence the beds containing 

 them are called ' mussel bands.' The two principal species are A . 

 robusta and A. acuta. The ferns are most commonly of the genera 

 Neuropteris and Alethopteris . The most remarkable fossil from these 

 nodules, found by Mr. E. Wilson in i 876 at Skegby New Colliery near 

 Mansfield, consists of five abdominal segments and a pair of pincers of a 

 scorpion, described and figured by Dr. H. Woodward 3 under the name 

 of Eoscorpius anglicus, being the first of its kind found in England. 



The roof of a coal seam, or stratum immediately following it, is 

 generally much richer in organisms, or perhaps more frequently examined, 

 than other portions of the strata, and constantly contains fragments of 

 such plants as Spbenopteris^ Aster ophyllites, etc., but these have not as yet 

 been adequately studied in Nottinghamshire. 



All the fossils hitherto mentioned, with the possible exception of 

 the fishes, are inhabitants of the land or fresh water ; and although in 

 other coalfields marine organisms occur at various horizons they have not 

 till lately been found in Nottinghamshire, probably from the scarcity of 

 opportunities. However, in the sinking of the shaft at Gedling (vide 

 infra) specimens ofLingu/a, Discina and Aviculopecten have been discovered 

 in bands, both connected with or unconnected with the coal seams in 

 that part of the Coal-Measures usually supposed to be characterized by 

 their absence. 4 



Notwithstanding, however, these proofs of occasional submergence, 

 as in other coalfields, the Coal-Measures exposed or worked in Notting- 

 hamshire are essentially non-marine, as is further shown by the remark- 



1 Nott. Nat. Sue. Transaction! for 1 894. 2 Also called Carbonicola. 



8 Quart. Journ. Geol. Sac. vol. xxxii. 4 Geol. Survey, 'Summary of Progress for 1902.' 



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