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XVI. — On the Fossil Plants of the Kilmarnock, Galston, and Kilwinning Coal Fields, 

 Ayrshire. By Kobert Kidston, F.K.S.E., F.G.S. (Plates I.-IV.) 



(Read 1st June 1891.) 



Introduction. 



The tract of land embraced in the area from which the fossils have been derived, that 

 form the subject of the present Memoir, extends in an easterly direction from Saltcoats 

 to Newmilns, a distance of about 19 miles. At both extremities, the Coal Measures 

 narrow down to under half a mile wide at Saltcoats, and about a mile broad at New- 

 milns. The greatest width is found towards the centre of the field, where in a north- 

 east and south-west direction it is over 12 miles broad. 



The whole of the Coal Measures occurring in Ayrshire are referable to the Lower 

 Coal Measures. The Lower Coal Measures contain, however, two well-marked groups : — 



I. An Upper Series of red and purple sandstones and clays, barren of coals. 

 II. A Lower Series consisting of grey, white, and yellow sandstones, dark shales, 

 fireclays, coal seams and ironstones. 



These two series of the Lower Coal Measures of Scotland are almost invariably 

 referred to by local geologists as the Upper and Lower Coal Measures. The terms 

 so used are not only misleading, but are inaccurate when applied to the Coal Measures 

 as developed in Britain. If we regard the British Coal Measures as a whole, and 

 in no other way can they be considered, if any satisfactory classification is to be 

 adopted, then the whole of the Scotch Coal Measures must be termed Lower Coal 

 Measures.* 



The Upper, Middle, and Lower Coal Measures are well developed in different parts 

 of England, and as typical localities where these may be seen, the following may be 

 mentioned : — 



Upper Coal Measures. — Radstock Coal Field, Somerset. 



Middle Coal Measures. — South Staffordshire Coal Field (Dudley), and part of the 

 Yorkshire Coal Field. 



Lower Coal Measures. — Part of the Yorkshire and Northumberland Coal Fields. 

 In the Coal Field of the Potteries, North Staffordshire, the three divisions of the 

 Coal Measures are present. 



One cannot insist too strongly on the absolute necessity of using definite and the 



* Perhaps certain beds in Fife may form an exception to this general statement, but that district requires further 

 investigation. 



VOL. XXXVII. PART II. (NO. 16). 2 Y 



