RUDI. 



912 



Rudistse in Connecticut river sandstone. Hitchcock's Ichn. 







I^"" 





mtc/uock. Scktk .J^asZ-^/^SS-, 



N. E. 1858, page 6, plate 5, fig. 2, of j{A^ ^w-Zy sAeZZ found (up 

 to 1858) in the New Bed sandstone of the Connecticut river 

 valley, which corresponds to the ''brown sandstone" and red 

 shale formation which runs in a broad belt across Pennsylva- 

 nia through Bucks, Montgomery, Chester, Berks, Lancaster, 

 York and Adams counties, and is commonly identified with the 

 Triassic formation of Europe, although its bottom division has 

 been suspected to be as old as the Permian^ and its uppermost 

 beds to be Lias or Oolite, The great scarcity of shells in it is 

 remarkable. Several outcrops (perhaps repetitions of one out- 

 crop) of JSii^A^/'m-bearing shale have been traced across New 

 Jersey into Pennsylvania; but almost the only fossils are foot- 

 prints of animals and insects. The specimen figured by Dr. 

 Hitchcock (preserved not petrified) is allied to Lamarck's Ru- 

 distce (a Sphmrulite^ or a ^^^^^^n^^), supposed to be confined 

 in Europe to the Chalk. In Virginia the plants ( Zamites^ etc.) 

 and four species of shells {Posidonomya^ and Cypris) suggest 

 2i Jurassic or lower Oolitic age. (W. B. Rogers.) At Mt. 

 Tom, Mass. Clathopteris rectiusoulus was found in the middle 

 of the sandstone mass, a European fern peculiar to the top of 

 the Trias and bottom of the Lias; so that the upper half may 



