172 MESSRS. KIRKBY AND DUFF ON THE 



24.— Black shale 2 



25.— COAL: supposed MARSHALL GREEN SEAM ... 1 5 



160 9 



The whole of the first of these bores appears to be in lower 

 Coal Measures which are thus shown to exceed six hundred feet 

 in thickness, though the excess is probably not great. 



Their position is precisely similar to the " G-anister Beds" or 

 Lower Coal Measures of Lancashire and Yorkshire ; but they 

 have not the development of the latter, nor yet are they known 

 to be characterised by those bands of Ooniatites and Aviculo- 

 pectens that distinguish the latter.* 



FOSSILS FOUND IN THE COAL MEASURES. 



The following list of fossil plants are those that have occurred 

 to us in the Etherley district. They are chiefly from the Brock- 

 well and Five Quarter or Busty coals ; but in some instances 

 they are from near the horizon of the Harvey or Yard coal, some 

 twenty fathoms above the Busty. 



They were obtained from the shale or "metal" immediately 

 overlying the coal, usually termed the roof of the seam. It was 

 not often that determinable species were observed in the coal 

 itself, though rude impressions of SigillaritB, with roots and 

 rootlets of Stigmaria, sometimes occurred in the body of the 

 seam. Our collecting ground however was the roof, from which 

 most of the species were obtained in situ underground. 



Therefore, in speaking of the plants characteristic of a coal 

 seam it will, of course, be understood that we refer to those 

 found in the deposit next above the seam, and not in the coal 

 itself. Neither do we wish to imply that the fossils found in the 

 roof were always of the kind whose remains formed the coal be- 

 neath. Certainly, where Sigillarice stumps are seen extending 

 up from the coal into the roof, or where the flattened stems of 

 innumerable Sigillarice are strewn over a seam of coal (resting 

 on the coal rather than imbedded in the roof matter), it is not a 



* See E. W. Binney, F.R.S., on Fossil Shells in the Lower Coal Measures, Trans. Man- 

 chester Geol. Soc. Vol. II., p. 72. 



