CAKBONIFEROUS^ GROUP. 91 



In the upper part of the Coal Measures of Shropshire, 

 Nobold, &c., near Shrewsbury, occurs a deposit supposed 

 to be of fi^sh-water origin, and extends for more than 

 thirty miles ; and in Coalbrook Dale, Mr. Prestwich has 

 described some beds with fresh-water shells (Unto) alter- 

 nating with others, containing marine remains (Nautilus, 

 Spiri/er, &c.,) thus inferring that a river emptied itself 

 into the ancient sea or estuary. In Yorkshire, and near 

 Edinburgh, somewhat similar phaenomena have been 

 observed. 



The characteristic fossils of the Coal Measures, are those 

 belonging to terrestial plants, as Pahns, Ferns, Calamites, 

 Lepidodendron and Coniferce, few traces of marine vegeta- 

 tion having been observed. The carboniferous limestone 

 abounds in marine testacea, the Brachiopoda {Troduct-m 

 Spirifer,) and Cephalopoda, (Goniotites, Orthoceras, &c.,) 

 forming a large proportion, and these are associated with 

 a great number of Crinoidea, and many Corals. 



LOCALITIES FOR FOSSILS, &c. 



At most of the eoal- workings, remains of plants may be obtained ; those 

 near Newcastle, in Coalbrook Dale, South Wales, and Radstock 

 and Camerton, Somerset, are good localites for procuring them. 



The limestone shales of Halifax, Yorkshire ; the shales and limestones 

 of Northumberland (Howick, Hetton, Beadnell, &c.,) ; the dis- 

 trict around BoUand, Yorkshire, and the limestones of Derbyshire 

 and Bristol, are a few places where the Mollusca and Crinoidea 

 may be obtained. In Ireland, Hook Point, near Weiford, Cork, 

 Fermanagh, and near Dublin. 



