Professor Keilhau on Contact Products. 153 



' h. '* The great repository of iron-ore in Elba, occurs as an 

 irregular mass, between slate and limestone " (F. Hoffmann, 

 in Kareten's Archiv., vol. xiii. p. 31). It is well known that 

 this slate is a very new one, and that a part of it contains 

 vegetable remains. 



«. At Sandomir, in Poland, the numerous masses of ore are 

 generally found at the boundary between transition-limestone 

 and a quartz ite-like sandstone, belonging to the same group 

 (a greywacke formation). (Pusch, Geognostische Beschreibung 

 von Polen, vol. i. p. 73). 



k. Near Kielee, in Poland, there occurs, resting on transi- 

 tion-limestone, a deposit of red sandstone, whose lowest bed 

 is impregnated, for a fathom, with lead-ore. This takes 

 place at several places in the same neighbourhood. As at 

 that locality the lead-ores otherwise belong exclusively to the 

 limestone, or to the transition series in general, Pusch (1. c. 

 p. 76), not without reason, also ascribes the so-to-speak 

 merely parasitic ore in the superimposed newer formation 

 to the limestone. 



/. The great bed of Miedzianagora, which contains copper, 

 iron, and manganese ores, and has been mined for centuries, 

 rests on calcareous slate, and is overlaid by quartz ite, with 

 strata of slaty clay (^^ Letten''^) and clay-slate ; the dip being 

 from 30° to 40°. The mean thickness of the bed of ore is 

 from 2 to 3 fathoms, and its known length is upwards of 3 

 English miles. Pusch instances a great number of similar 

 cases in the same district, in which the ore is met with in the 

 same position, close to the junction of the limestone and 

 quartz-rock (1. c. p. 76-91). 



m. The beds of hematite, occurring in the southern dis- 

 tricts of the State of New York, usually lie near the junc- 

 tion of the talcose slate-formation with a newer limestone. 

 (Silliman's Journal, vol. xl. pp. 75, 76). 



n. In New York, masses of iron-glance occur as a contact- 

 formation. The position of these sometimes extremely large 

 repositories of ore " is confined to the upper portion of the 

 primary strata, and the lower layers of the Potsdam sand- 

 stone," (1. c. pp. 81 and 82). 



0. In Wales, in the midst of Cambrian slates and grey- 



