GEOLOGICAL SOCIETY. 



39 



Geological Society of Pennsylvania, and let me know 

 the result of your decisions. The most extraordinary 

 thing connected with these fossils is, that they were 

 found in a magnetic iron ore, the protoxide mixed with 

 the peroxide and clay slate. The walls of the bed are 

 of the same, or nearly the same date with the bed of the 

 ore, for they are filled with terebratulse." 



In a communication recently made to the Geological 

 Society of London, by J. Prestroich, Jr. Esq. "on 

 some of the faults which affect the coal field of Coal- 

 brookdale," the author concludes his memoir with some 

 observations on the fossils he procured, principally from 

 the ironstone of the coal measures ; among the most re- 

 markable, were the remains of some trilobites, hitherto 

 undescribed. They were procured from a bed of iron- 

 stone in the centre of the coal measures. No descrip- 

 tion of these animals being, to my knowledge, yet given, 

 it is impossible to say what affinities they may have to 

 our Jlsaphus crypturus. Mr. Prestrioch, who notices 

 a coleopterous insect, and another apparently belonging 

 to the genus Aranea, which were obtained from the 

 ironstone nodules. The occurrence of these different 

 races of animals in the same formation, is certainly a 

 very curious and highly important fact. 



