127 



TAB. CCCLXVIII. 



F E R RUM quartzosum. 

 Siliceous Iron-Stone. 



Class 3. Metals. Order 3. Mixed. 



JVIany places afford Iron-stones, Geods, &c. See De- 

 scriptions and Plates 106 and 107 *• The present specimen 

 is from under the Thames at Rotherhithe, where the Tun- 

 nel is perforated, in a mixture of Sand, Sandy Lime, &c. 

 It is remarkable for its branching, and in some specimens 

 so much so as to represent the more entangled roots of trees. 

 It is internally of a raw brown umber colour, nearly compact 

 appearance, and may be scratched with a pin, giving a 

 whitish streak : externally more or less rugged, with Lime 

 and Sand attached to it. I have only one instance of its 

 being found elsewhere, and that is a larger specimen in the 

 possession of Mr. Smith, who is so well known to be con- 

 versant with most of the Strata of this Island, who found it 

 in Wiltshire. The Iron in this specimen is in a low state 

 of oxidizement, and is intimately combined with Silex and 

 other earthy matter, as with a little heat it becomes mag- 

 netic. Some of my specimens are the more extraordinary 

 for having little Geods about the size of hazel-nuts, with 



* I omitted one of the usual ferms for Iron-Stones, which is Geods. The 

 term seems to be original with Sir John Hill in his History of Fossils, page 

 541, where he describes them as "crnslated ferruginous bodies, holding loose 

 earthy or arenaceous matter."' He has made distinctions regarding more 

 solid coated varieties, &c. as Hetrop; ra, Empheiepyra, &c. 



