Geology. 163 



by crushing the little tyrants before I had time to complete 

 my experiments on them. — F, C. Lukzs, Guernsey^ Aug. 7. 

 1832. 



Geology. — Additional Information on the Fucbldes allegha- 

 nimsis. (p. 27.) — Nov. 11, 12. 1833. Two days' examination 

 along the slope of the Shade Mountain, in Juniata Valley, has 

 materially enlarged my knowledge of the geological position of 

 this fossil. On the banks of the Pennsylvania canal, near Lewis- 

 town*, the strata consist of numerous seams from 1 in. to 

 H ft* thick, of argillaceous sandstone, more or less ferruginous, 

 and varying in colour from dark brown to greenish blue. These 

 are quarried in large slabs for the purposes of paving and 

 building. The surfaces of these slabs are covered with i^uci 

 in relief, whose forms are ill defined, and are smaller than the 

 Fucoides alleghaniensis ; they are also separated by courses 

 of soft argillaceous rock, from ^ in. to 1 in. in thickness, con- 

 sisting almost entirely of similar i^uci. An opening, made 

 into another part of the series, at a lower position, and at the 

 distance of half a mile, exhibited no fewer than a hundred suc- 

 cessive courses of these vegetable deposits upon similar rock, 

 within a section of only 20 ft. perpendicular. All these fossil 

 beds comprise the same undefined Fucoides, occasionally tra- 

 versed by the larger species. I traced a succession of these 

 beds to upwards of 200 ft. elevation. At the height of full 

 350 ft., the Fucoides alleghaniensis prevailed in abundance 

 upon slabs of brown red sandstone, and probably extended 

 50 ft* higher. The whole series, therefore, which contains 

 fossil Fuel occupies a thickness of from 250 ft. to 400 ft. 



Nov. 21. 1833. In traversing the parallel ridges called the 

 Seven Mountains, at the distance of 15 miles west of the 

 Shade Mountain just noticed, the Fucoides alleghaniensis 

 appears on the surface of white sandstone strata, occupying a 

 mile in breadth, and rising to the height of 1000 ft. 



Dec. 6. 1833. In Murney Ridge, 50 miles north of the 

 Shade Mountain, and running parallel with, and at the dis- 

 tance of 15 miles east of, the Alleghany Mountains, I again 

 observed splendid specimens of F. alleghaniensis. 



I notice these localities, the detail of which is only interest- 

 ing to show that this remarkable fossil is repeated at various 

 and distant parts of the transition series in this country. — 

 R. (7. Taylor. Lemstown^ Pennsylvania, Jan, 1. 1834. 



* Upon this spot I observed growing that magnificent tree the Catdlpa 

 syiingce^oWsiy and groups of the medicinal shrub, Acacia marilandica. At 

 400 ft. higher, the mountain was covered with the common acacia, or 

 prickly locust tree (Robinfa Pseud-^cacia X.), amongst scrubby chestnuts 

 and rock oaks and sumachs. 



M 2 



