1879.] ^"5 



who obtained it (with several others) from a miner in the 

 Peach Bottom slate quarries on the Susquehanna river near 

 the Maryland State Line. The other slabs are in the York 

 Museum, in York County, Pennsylvania. The species of 

 fucoid was determined by Prof. Lesquereux from a careful 

 drawing, which he pronounced sufficiently characteristic. 



The great importance of this discovery in confirming the 

 long suggested possible existence of Hudson river slates 

 (Lower Silurian, No. Ill) so metamorphosed as to be almost 

 totally destitute of organic remains, in the so-called sub- 

 palseozoic, hypozoic, hypazoic, azoic, or eozoic (Huronian, 

 Cambrian, or Laurentian) belt of the Atlantic sea coast, was 

 dilated upon and discussed by Prof. Lesley, Prof. Frazer, 

 Prof. Cope, and Prof. Hayden. Mr. Lesley said : 



Prof. Lesquereux has just determined Buthotrephis flexuosa on a slab of 

 roofing slate from the quarries on the Susquehanna river near the Mary- 

 land line. This is a most important discovery. Prof. Frazer has been 

 studying the roofing slate belt and adjoining chlorites for several years in 

 connection with his York and Lancaster county work. He never found 

 any traces of organic life, nor could hear of any. But he found several 

 curious forms in the rocks across the State line in Maryland, one of which 

 looked like a flattened Orthoceras. Prof. James Hall and Mr. Whitfield 

 were disposed to consider them not organic. They have been figured for the 

 American Philosophical Society's Proceedings and for the Reports of the 

 Survey. These are the only fossils ever seen in that region to our knowl- 

 edge. The slab of B. flexuosa, is in our Museum and will be figured. Prof. 

 Frazer received it from a Presbyterian clergyman, President I. N. Ren- 

 dall of Lincoln University, who got it from a miner, as part of a mass four 

 or five times as large, the remainder of which he sent to the York Mu- 

 seum, York, Penna., in acknowledgment of aid from the citizens to the 

 university. There seems to be no doubt that the slabs came from the 

 Peach Bottom quarries as asserted. 



There are two species of Buthotrephis known, one in the Trenton, three 

 in the Hudson river slates, one in the Clinton. One is reported from the 

 Devonian of Russia. Several from the Subearboniferous remain unstudied. 

 B. flexuosa is characteristic of ihe Hudson river. It is in the upper part 

 of the Hudson river formation, along the foot of the Kittatiny or Blue or 

 North Mountain, on the Lehigh river, in eastern Pennsylvania, that we 

 have our Slatington and other roofing slate quarries ; and no trap is known 

 in the neighborhood, and no reason can be assigned for excessive metamor- 

 phosis of structure (not of lithology) ; but on the Maryland line, a trap dyke 

 many miles long has been followed by Prof. Frazer, across Lancaster 



PROC. AMER. PHILOS. SOC. XVIII. 104. 2u. PRINTED DEC. 30, 1879. 



