276 Peacock: Lines. Naturalists at Linwood Warren. 



keeper of the geological department has kindly sent me a list in 

 return. They are all from the Kimeridge Clay, and Mr. Lewington 

 would be happy to collect for any student interested in these 

 beds : — 



Nucula menkii Rcemer. 

 Astarte supracorallina D'Orb. 

 Ostrea sp. (flabelloides ?). 

 Area longipunctata Blake. 

 Area reticulata Blake. 

 Anatina sp. ? 



Trigonia juddiana Lycett. 

 Rostellaria sp. ? 



Rostellaria rasenensis Blake. 

 Cerithium crebrum Blake. 

 Cerithium forticostatum Blake. 

 Amm. (Cardioceras) serratus 



J.deC.Sowerby. 

 Amm. (Perisphinctes) triplicatus 

 J.Sowerby 



We came across the scoriae of ancient British iron-smeltings 

 on the Warren. It was no doubt the remains of. the hydrated 

 ferric oxide of the ' pan-iron ' which in sandy soils plays the 

 part of a cementing- agent, as can be seen here, and on Manton, 

 and at Scotton Common.* In such moor soils, especially those 

 covered by heather as Linwood, the iron has been dissolved out 

 of the surface soil by the action of the humic acids, the sands 

 on the surface being left remarkably white. The iron passes in 

 solution into the subsoil, where it is re-precipitated, with the 

 result that the sand at a certain depth is cemented together, and 

 an iron-stone produced. This precipitation of the iron oxide 

 may be brought about by contact with calcium carbonate 

 contained in the subsoil, but that can hardly be the case at 

 Linwood. It is more likely the whole action of solution and 

 precipitation is determined by alterations in the condition of the 

 soil. In autumn and early winter, while saturated with water, 

 the iron may enter into solution as a ferrous salt, and be carried 

 below ; and in summer time, in a dry and aerated soil, it may 

 be precipitated as ferric oxide. The iron pan w r ould naturally be 

 formed at the line in the subsoil at which oxidation chiefly 

 occurred. Where two or more pans are found one above 

 another, as on Manton Warren, the line of oxidation has been 

 suddenly changed by sand drifting heavily above. The whole 

 matter is one which requires further stud}'. 



A high tea was provided for the visitors at Market Rasen 

 after the excursion, the Mayor of Louth (Mr. S. Gresswell), 

 senior vice-president of the Louth Society, presiding with his 

 usual felicitous kindness. 



"See Prof. R. Warington's ' Physical Properties of Soil,' Oxford, 1900, 

 and other authorities. 



Naturalist, 



