1885.] 4U<J [Frazer. 



which forms its eastern boundary, is very generally a conglomerate of 

 the older limestone pebbles, forming Mesozoic rocks. This can be ob- 

 served about two miles west of York, at Beeler's Cross roads (Vol. C, p. 

 92, Sec. 2a). 



The upper bed seems to be also a conglomerate which forms its 

 western boundary on the slope of the South mountain. Rogers was in 

 doubt, whether the so-called " Potomac marble " was represented by the 

 upper or lower of these (see Report CO., p. 265). Borings with the dia- 

 mond drill by Mr. Heinrich, recorded in the paper above mentioned, show 

 that no such thickness exists in point of fact as one might conclude from 

 the appearance of the beds, and the probability is that the actual thickness 

 there is not above fifteen hundred feet. No such borings have been made 

 in York county, but the probability is that this thickness is not very 

 greatly exceeded. But these measures in York county are chiefly interest- 

 ing on account, 1st of their fossils ; 2d of their iron ores ; and 3d of their 

 coal. From the former Prof. E. D. Cope was able to assign the beds con- 

 taining them to the middle and upper divisions of the Triassic. The coal 

 which is found about three-quarters of a mile norlh of Liverpool on I. 

 Spahn's farm, and elsewhere, represents the extensive deposits known as 

 the Richmond Coal fields, which have been wrought for a century in 

 Virginia to advantage, and are so still. Although its analysis indicates it 

 to be a good bituminous coal (see CCC, p. 259*), yet it has never been 

 found in Pennsylvania in paying quantities. 



Copper, and other valuable metals have been similarly observed in this 

 formation, though in disappointing quantity, in this county, though they 

 have supplied furnaces in other parts of this State and in other States. 

 The richest deposits of these metals are usually found near the borders of 

 the formation. For the following summary of the Triassic fossils as yet 

 determined in Pennsylvania I am indebted to the kindness of Prof. Cope. 



The vertebrate fossils from the Triassic beds of Pennsylvania have 

 been obtained principally from two localities by Mr. C. M. Wheatley. 

 The longest known is the tunnel of the Reading railroad at Phoenixville; 

 the other is in York county. f The species represented belong to the 

 Fishes, Batrachia and Reptilia, as follows : 

 Fishes. 



Turseodus acutus Leidy .Phrenixville. 



Batrachia. 



Eupelor durus Cope Phoenixville. 



Reptilia. 



Belodon prisms Leidy York Co., Phoenixville. 



" carolinensis Emmons York Co., Phoenixville. 



" Upturns Cope Phoenixville. 



* See Note 5 at the end. 



f About two miles north of west of Emilysville and one and a half mUes from 

 the south-eastern border of the Mesozoic— P. F. 



