338 Jose^jh Lucas — The Permian Beds, 



chronological one. We should not however on this account be 

 entitled to regard them all as representing a single species ; for it is 

 by far the most likely that true zoological characters would be found 

 if an opportunity existed of examining in the fossils the soft parts 

 now entirely lost, more especially when we bear in mind that these 

 fossils belong to periods separated from one another by such long 

 intervals of time as those which intervene between the Cretaceous, 

 Miocene, Pliocene, and existing epochs. 



Under these circumstances, there is no reason against assigning 

 also to the Coralline Crag species a distinguishing name; and though 

 no available zoological characters can be found on which a diagnosis 

 may be based, the geological position of the hydroid may con- 

 veniently suggest the purely provisional designation of Eydractinia 

 pliocena. 



II. — The Permian Beds of Yokkshire. 

 By Joseph Lucas, F.G.S., 

 of the Geological Survey of England and Wales. 



IN the March number of the Geological Magazine, Mr. A. H. 

 G-reen observes that it is difficult to account for the supply of 

 salts to the Permian Sea. For the iron, he calls in the aid of minei'al 

 springs produced by volcanic action ; but for the lime and magnesia, 

 streams flowing into the sea holding in solution bicarbonate of lime 

 and sulphate of magnesia. 



Now, at present, the Magnesian Limestone rests on Coal-measures, 

 Millstone-grit, and nearly touches Yoredale Limestones, near the 

 Swale. The Millstone-grit alone might furnish iron enough, ^ to say 

 nothing of other bordering formations. All over its surface now 

 thousands of chalybeate or ferruginous springs break out, some of 

 them most copiously charged with iron. The whole system is re- 

 plete with iron,^ as appears from the quantity which is seen at the 

 surface in the form of oxide. It is quite the exception to find 

 sandstones unstained by oxide of iron, and in a less degree the same 

 is true of the shales which often contain beds of ironstone. Certain 

 beds are so full of it that when seen in section they are of the 

 brightest red. One such I have traced for more than fifteen miles. 

 It is a coarse grit full of cavities containing an ochreous powder, 

 and sometimes red felspar. When ploughed, it forms a silky, 

 bright-red soil. It also contains fragments of Encrinites and shells. 

 Thus there is a bed in the Millstone-grit series, which, when free 

 from drift, colours fields quite as bright a red as the Magnesian 

 Limestone does, and whose existence implies an amount of concen- 

 tration scarcely inferior to that required for the formation of red 

 beds in the New Eed Sandstone. From its conspicuous colour it 



^ Mr. David Forbes says that " many beds, for instance the Gault, contain more iron 

 than those which are now red, though they may be grey or blue." 



* In the form of bisulphide and carbonate. I have found iron pyrites in shales in 

 Nidderdale, and bands and nodular beds of clay ironstone in many places. 



