Mr. Weaver on the Geological Relations of the South of Ireland. 63 



in width from a few inches to two or three feet ; but some of them were found to be discontinuous 

 upon the line of range, terminating in threads. From the excavations made, about ten tons of 

 lead ore were raised. 



The sandstone rock in this northern face of Sliallee mountain, is disposed in firm whitish or 

 yellowish strata, two and three feet thick, dipping 33° to the north, consisting chiefly of fine grains 

 of quartz closely compacted, and more or less micaceous. In a denuded portion of this rock, 

 about ten fathoms square, I counted at least twenty veins of sulphate of baryies, varying from the 

 size of a thread to two or three inches in width, traversing the sandstone mostly in a direction 

 approaching north and south, but traceable in part to their termination in a filament. These, as 

 well as those bearing lead ore, are evidently all veins of segregation, or of contemporaneous forma- 

 tion with the sandstone, commonly traversing the latter in the line of the dip. 



(77.) In the Carboniferous Limestone. — The portion of the limestone field 

 contained in the Map, has hitherto yielded no important ground for mining 



opinions expressed, on this subject, by Professor Sill! man' and Dr. Harlan 2, appear to cor- 

 respond. In further corroboration of this view, it may be added, that both the antliracitous and 

 bituminous coal regions in Pennsylvania, produce large quantiiies of clay-ironstone, the usual 

 concomitant of the coal-fields of the great carboniferous order. 



This distribution of the coal in Pennsylvania, anthracitous on the east and bituminous on the 

 west, may be compared with the coal deposits in South Wales, where the eastern portions are bitu- 

 minous and the western anthracitous ; and again with those in Ireland, where the northern deposits 

 are bituminous, and the southern anthracitous. But both the Welsh and Irish coal-fields belong 

 to the great carboniferous order ; and I anticipate that such also will be admitted to be the case 

 with respect to the Pennsylvanijn, which point indeed, in reference to the north-eastern parts of 

 that State, appears to me fully established by Professor Eaton, though obscured by a peculiar 

 diction. The mere quality of coal, as being anthracitous, cannot alone be considered a decisive 

 criterion of its antiquity, though so conceived by some geologists. On the other hand, however, 

 it maybe asked, is there any well-authenticated instance of a bed of 6iiie?w?noM« coal having ever 

 yet been found within the limits of the transition system? I am not aware of such. 



I will here only add the general remark, that if the land of the United States be rich in the vege- 

 table productions of warm and temperate climates, it is no less so in the exuberance of its mineral 

 stores, of which the chief are its inexhaustible deposits of coal and iron, the mainsprings of arts 

 and manufiictures. In the possession of such treasures, combined with a spirit of activity fostered 

 by free institutions, and the natural and gradually improving facilities of internal and external 

 communication, our American brethren may well aspire to the attainment of a state of greatness 

 and prosperity, not readily brought within the compass of human calculation^. (May 1837.) 



' American Journal of Science, vol. xix. p. 12. 



- Transactions of the Geological Society of Pennsylvania, vol. i. p. 258. 



3 For some other details in exposition of the subject of this note, see also my notices in the 

 Lond. and Edinb. Phil. Mag. for August 1836, and May 1837. And as a corroboration of 

 several of my views in relation to the State of New York, I would refer the reader to Remarks on 

 the Geology of Western New York, by Geo. E. Hayes, dated Oct. 1836. See American Journal 

 of Science, vol 31, pp. 241 to 247, which has come to my hands since the preceding pages were 

 written. But to reconcile our language, I should observe that the author employs the term upper 

 transition instead of carboniferous series. It may also be useful to remark, that with American 

 geologists, greywacke slate often implies sandy or quartzy shale of the coal measures ; lias, 

 argillaceous carboniferous limestone; and oolite, an oolitic variety of that formation. (May 1837.) 



