115 



possesses the character of a marble, being susceptible of a good 

 polish, and resembliiig certain highly variegated breccias. 



Though this conglomerate constitutes the uppermost member 

 of the red sandstone group in various places, both in New Jersey 

 and Pennsylvania, there are other neighbourhoods, for example, 

 near Bainbridge, on the Susquehanna, where it would seem rather 

 to occupy a position at the base of the series. All these rocks 

 of the middle secondary date, of which the argillaceous red and 

 brown sandstone is the predominant and characteristic variety, 

 appear, from numerous geological indications, to have been pro- 

 duced at a period subsequent to the elevation of the lower secon- 

 dary strata, including the coal deposits. They seem to have origi- 

 nated in a long narrow trough, wliich had its source as far south 

 at least as the eastern base of the Blue Ridge in Virginia and 

 North Carolina, and which probably opened into the ocean some- 

 where near the present position of the Raritan and New York 

 bays. Their materials give evidence of having been swept into 

 this estuary, or great ancient river, from the south and southeast, 

 by a current producing an almost universal dip of the beds 

 towards the northwest, a feature clearly not caused by any up- 

 lifting agency, but assumed originally at the time of their deposi- 

 tion, in consequence of the setting of the current from the opposite 

 or southeastern shore. 



Numerous ridges and dikes of trap, some of them many miles 

 in length, traverse the area occupied by this formation in Nev/ 

 Jersey. The date of their appearance at the surface was mani- 

 festly subsequent to the deposition of the red argillaceous strata 

 through which they have burst, overflowing, while in the melted 

 state, the adjacent beds, and greatly altering their texture, colour, 

 and mineral aspect. 



In what exact period during the secondary ages of the earth's 

 geological history, this widely-diff'used series of sedimentary 

 strata, and their accompanying igneous rocks, originated, we are 

 at present unable to determine with strict scientific precision, but 

 we are not without data for a somewhat satisfactory approxi- 

 mation. 



The organic remains hitherto discovered are extremely few, 

 and the evidence tliey afibrd is not sufficient to establish within 

 near limits the era to which these strata should be referred. 



