Frazer.] 4LM [Dec. 4, 



Palmosaurus fraserianus Cope York Co. 



SucJioprion cyphodon Cope York Co. 



" aulacodus Cope York Co. 



Clepsysaurus pennsylvanicus Lea Phcenixville. 



" veatteianus Cope York Co. 



Palceoctonus appalachianus Cope York Co. 



1 hecodontosaurus gibbidens Cope York Co. 



Total, twelve species, most of which are descrihed in the Proceedings 

 of the American Philosophical Society for 1877. 



Of the above, the genera Belodon, Palseosaurus and Thecodontosaurus 

 are typical Triassic forms. The first and last named are the most clearly 

 determined. Belodon is characteristic of the Keuper in Europe. As the 

 species found in North Carolina and in New Mexico (B. scolopax and B. 

 buceros Cope) are characteristic members of the genus, I have identified 

 their horizons with the Keuper. The specimens from Pennsylvania are 

 not so perfect as from the Other localities, but are not separable from 

 them. Thecodontosaurus belongs to the base of the Keuper (Etheridge). 

 No vertebrate remains indicating the existence of the Muschelkalk 

 have yet been found in North America. — E. D. Cope. 



Iron Ores. What has been said of the copper and other metals, 

 may here be said of the iron ores. Although an immense amount of iron 

 must have been consumed in providing these beds with their characteristic 

 red color, and in fact large quantities of thin oxide scales are to be ob- 

 served almost everywhere between the strata ; the only localities where 

 iron ores appear to have been found in any abundance or permanence 

 are : 1st, those near the margins of the New Red Sandstone, when it 

 overlies another formation containing iron ore ; and 2d, in the neighbor- 

 hood of the trap dykes, which contain over 11 per cent of oxide of iron.* 

 In the former case, it is extremely probable that the deposits of the older 

 beds (as on the flank of South mountain) have been torn up by the agi- 

 tated waters which laid down the Triassic rocks, and redistributed as part 

 of the latter. In the other case it is very probable that after the decay of 

 the exposed portions of the Trap, part of their iron oxide contents was 

 concentrated by natural water-flow, and carried into the cavities and 

 seams of the porous Mesozoic rocks. The Traps, probably, not only sup- 

 plied the original material for these ore beds, but in addition protected 

 them from being washed away, and new outbursts of molten rock very 

 likely gave them their altered appearance and magnetic character. 



The Trap. Though the trap cannot be said to be of the same age as the 

 Triassic (since it cuts through the highest beds and therefore appeared 

 clearly after the latest sedimentary bed of the Mesozoic), still there is no 

 sense. The most interesting features of the York county trap are its ap- 

 pearance sometimes as dykes cutting through narrow clefts of the rocks, 

 and sometimes as mesas, or "tables" covering large areas after having 



* See Note G at the end. 



