82 STEVENSON— FORMATION OF COAL BEDS. [April i8, 



Fragments of rock are the foreign bodies which are the most per- 

 plexing. The earliest recorded observation seems to be that by 

 Phillips in 1865, followed by that of Noeggerath in 1862, both of 

 which have been cited by Stur. Roemer"^ soon afterward described 

 3 small fragments from a coal bed in Upper Silesia; they were of 

 crystalHne rock, unlike anything known in Silesia. E. B. Andrews 

 in 1870 announced the discovery of a waterworn quartzite fragment 

 in the coal at Zaleski, Ohio, half embedded in the coal. Newberry in 

 1874 saw a fragment of talcose slate in the parting of Coal No. i 

 at Mineral Ridge, Ohio, which he thought might have come from the 

 Canadian Highlands; somewhat later he found a rounded quartzite 

 fragment in the Block coal, resembling a Huronian rock in Canada. 

 Stevenson in 1877 reported the discovery of a waterworn limestone 

 bowlder embedded in the Sewickley coal of Fayette county, Penn- 

 sylvania. It was about 2 feet in diameter and extended above as 

 well as below the coal. He believed that it had not been deposited 

 prior to the coal, for that was splashed as though the fragment had 

 fallen into soft material. Similar notices appeared from time to 

 time but in all cases they were merely casual. 



Stur^° in 1885 gave a summary statement of knowledge re- 

 specting such occurrences. He notes the discovery by Roemer in 

 1883 of a mass weighing 55 kilogrammes, granite such as is unknown 

 in the region. He adds instances coming under his own observa- 

 tion in several Austrian coal fields, but the notes refer to somewhat 

 widely separated localities and the fragments are of small size. 

 Radcliffe^^ described 6 bowlders from Dukenfield, England, em- 

 bedded partly in the coal and partly in the overlying shale. The 

 portion within the coal had a coaly crust but no such crust appears 

 on the part within the shale. All are of quartzite and the weight 

 was 5 to 166 pounds. One specimen was on edge. W. B. Dawkins 



"F. Roemer, "Ueber das Vorkommen von Gneiss- und Granulit-Geschieben 

 in einem Steinkohlenflotze oberschlesiens," Zeitsch. Dentsch. Geol. GeselL, 

 Band XVI., 1864, pp. 615-617. 



*" D. Stur, " Ueber die in Flotzen reiner Steinkohle enthaltenen Stein- 

 Rundmassen," etc., pp. 613-647. 



" J. Radclifife, "On Grooves and Quartzite Boulders in the Roger Mine of 

 Dukenfield," Quart. Jonrn. Geol. Soc, Vol. XLIIL, 1887, pp. 601, 603, 604. 



