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204 NEW YORK STATE MUSEUM 



Jersey F. helderbergiae is very abundant in the lowest 

 Coeymans. In southern New York a few specimens have been noted 

 in the upper ManHus. 



Among- bryozoa the genus Orthopora is recorded by Schuchert 

 from the upper IManHus of Maryland. This is, according to 

 Nickles and Bassler [1900] its earliest appearance. It is next found 

 in the Helderbergian, where it is abundantly represented in the 

 upper Coeymans and lower New Scotland of Trilobite mountain. 



Gypidula galeata makes its first appearance in the upper 

 Manlius of western Maryland as a small variety. This is here ex- 

 ceedingly abundant. It has not been found in the New York or New 

 Jersey Manlius but the normal form appears in great numbers in 

 the lower Coeymans ; it is not present, however, in the Manlius- 

 Coeymans transition (Favosites bed). 



Leptocoelia flabellites occurs as a small variety in 

 the Becraft of Maryland but not below the upper division of the 

 Oriskany at Trilobite mountain. 



B e a c h i a s u e s s a n a appears in the lower Oriskany of 

 western Maryland as the variety i m m a t u r a . These basal beds . 

 are probably contemporaneous with part of the Port Ewen of New 

 York, since the latter are not recognized in Maryland and there 

 was a continuous deposition. The first appearance of this species 

 in Nev\^ Jersey and New York was in the lower Oriskany. 



These species appear to indicate a northward migration. M 



DETAILED DISCUSSION OF THE STRATA AND FAUNAS OF THE VARIOUS 

 FORMATIONS AT TRILOBITE MOUNTAIN ff 



Less than one eighth of a mile east of the tollgate which is at 

 the southwest terminus of Trilobite mountain, is the road leading 

 along the southeastern foot of the mountain. This may be called 

 for convenience the Bennett road from the Bennett's limestone quar- 

 ries which are situated by its side, and is, as noted on the sketch 

 map, a public road for about one half the distance. Beyond this it 

 is either a rough wood road or a mere foot path. It is along this 

 road that the following sections begin, passing northwestward across 

 the strike of the beds. The mountain, with the slight exception 



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