Lesley.] 478 [December. 



Conecoeheague, seven miles, to the Caledonia and Pond-banks, and 

 thence forward along the ore belt, tv:o miles, to the Home-bank, 

 and one mile further to Mont Alto Furnace, making ten miles in all, 

 is about to be constructed. The route follows a wide and shallow 

 meadow valley, with a rise (by barometer) of 20 feet in the first 

 four miles ; 90 feet in the next three miles, to the first ore beds ; and 

 230 feet for the next two miles, to the Home-bank opening. 



The water of the creek at the furnace is 140 feet below the Home- 

 bank, and 200 feet above railroad grade at Scotland Station (mea- 

 sured by one of Becker & Sons' Aneroid Barometers). 



It is within a few hundred feet of one of the Pond-banks that the 

 shaft has been sunk, which penetrated the lignite layers ; and it will 

 be noticed, that their horizontality is in agreement, 1st, with the 

 horizontality of all the Silurian measures which sweep round the flat 

 south end of the Little Mountain anticlinal ; 2dly, with the horizon- 

 tality of the ore deposits; and, 3dly, with the general plane surface 

 of the locality. There is no good objection to considering the lignite 

 beds a local deposit of late date, made in a shallow pond, produced 

 either by erosion, or by settling, caused by cavern-solution close under- 

 neath, and puddled with the ore-clay so as to hold water and maintain 

 a fresh-water vegetation, with which the forest leaves and trees, in- 

 cessantly discharged by freshets, would be intermingled. This may 

 have happened at any age after the uplift of the palaeozoic system and 

 the subsequent production of the present surface, except so much 

 time as may be represented by the forty feet of sand, &c. lying upon 

 the lignite. There is, therefore, to choose from, the whole interval 

 embraced by the Permian, Jurassic, Cretaceous, and Tertiary areas. 



To determine this more nearly, there must first be a determination 

 of the relation existing between the surface of the Palaeozoic region 

 and the surface of the Permiano-Jurassic region, commonly sepa- 

 rated from each other by the mountain barrier of the Highland- 

 South-Mouutain-Blue-Bidge range, but touching each other along 

 the remarkable gap in that range, between the Schuylkill and Sus- 

 quehanna rivers, and represented on the colored map, plate XI. The 

 present relation of the two surfaces to each other, is shown in Fig. 10, 

 plate X, and a selection from some of their supposed relationships in 

 past times is made in Fig. 11. The so-called New Red Estuary rocks 

 are seen in these sections dipping uniformly northwestward, at angles 

 from 20° to 30°. Their highest stratum, the breccia called Poto- 

 mac Marble, is sometimes a conglomerate of well-rolled pebbles, in 

 which I have often recognized, not only fragments of the Lower 



