1897.] NEW YORK ACADEMY OF SCIENCES. 241 



Bolton and Bury Area. 



The chief fault is that known as the great Irwell valley fault, 

 having a, downthrow to the east of over 1,000 yards, and crossing 

 the whole of south Lancashire. Further to the south it is con- 

 tinued into the Trias of Cheshire. 



A great fault bounds the northeast border of the Manchester 

 coal field and, passing N. N. W. across the Trias, runs fairly 

 parallel to the Irwell valley fault, across the coal field to a 

 little west of Bury. 



Wigan and St. Helens District. 



The main faults of this district are the great Upholland fault 

 with a downthrow of 650 yards and a set of five faults at nearly 

 equal distance of 1,400 yards from one another. These are : 



1. Great Pemberton Fault. 



2. Great Shevington Fault. 



3. Giants Hall Fault. 



4. Great Standish Fault. 



5. Great Haigh Fault. 



All the faults mentioned thus far belong to the N. N. W. or 

 post-Jurassic System. They are accompanied by smaller faults 

 which run out from them at acute angles or remain parallel, and 

 by a system of east and west faults of less importance which 

 break up the ground between them. This latter series was 

 doubtless in part developed when the Pendle range system of 

 folds were formed. 



Coal Measure Flora. 



The flora of the Lancashire Coal Measures has long been 

 famous, largely because of the excellent preservation of vegetable 

 tissues in nodules overlying the Bullion Seam or Upper Foot 

 Coal. These nodules supplied material to Binney, Carruthers, 

 Williamson, Lindley, Hutton, Brongniart, Solms, Laubach and 

 Hick, whereby they were enabled to throw a flood of light upon 

 the structure and relationship of the Coal Flora. 



The study of the minute structure of coal plants has also been 

 a favorite subject with the miners, and many can be found to-day 

 with valuable cabinets of coal slides and all the machinery neces- 

 sary for their production. Their knowledge of the structure of 

 these plants is considerable, and "Williamson and others have 

 testified repeatedly to the energy and skill with which these men 

 have prosecuted their studies and produced valuable results. 



The study of the external features of coal plants has not 

 been followed so assiduously, probably because of a perplexing 



Transactions N. Y. Acad. Sci., Vol. XVI., Sig. 16, July 17, 1897. 



