116 white: age of the Worcester phyllite 



gneiss, on the east, the sediments having been more argillaceous 

 westward, and more arenaceous eastward. The Brimfield schist, 

 described by Emerson and Perry as overlying their Paxton schist, 

 is accordingly correlated by them as a more highly metamorphosed 

 phase of the Worcester phyllite. 



Tho these beds were described more than three-quarters of a 

 century ago and have been visited by scores of geologists, the 

 widest views have prevailed regarding their age. As often hap- 

 pens in graphitic argillites, mineral or cleavage forms accidentally 

 resembling graphitized remains of plant fragments are plenti- 

 ful. Some of these closely imitate imperfect fragments of Cor- 

 daites, Calamites, Lepidodendron, etc. In 1883 a specimen was 

 found by Professor Perry which appeared to be a true fossil, con- 

 sisting of a fragment of a Lepidodendron stem impression, in 

 which the somewhat indistinct leaf cushions were still compar- 

 atively regular in their quincunxial arrangement. This specimen 

 was submitted by Perry to Leo Lesquereux, 3 who regarded it 

 as probably belonging to Lepidodendron acuminatum, a Carbon- 

 iferous species. On the evidence of the relatively minor degree 

 of alteration, the occurrence of the graphitic bed, and this unfor- 

 tunately rather obscure fossil, 4 Perry and Emerson have courage- 

 ously insisted on the Carboniferous age of the phyllite, notwith- 

 standing the scepticism of most geologists and paleontologists, 

 some of whom, denying the validity of the fossil, have continued 

 to regard the beds as not younger than Algonkian. Spurred by 

 criticism, Professor Perry continued the search, with the result 

 that after sixteen years the counterpart or reverse of the same 

 stem fragment impression was discovered. This side, however, 

 was scarcely more distinct than the other, and accordingly added 

 nothing to the evidence as to the age of the phyllite. 



Since it was evident that in the midst of soft clay shales, after 

 such squeezing and alteration as at Worcester, there could be 



3 Am. Jour. Sci., Vol. XXIX, 1885, p. 157. See frontispiece "Geology of Wor- 

 cester, Mass.," 190H. 



4 Another specimen, never reported on by a paleontologist, is said to have been 

 sent to Columbia University. 



