342 A. Wing's Discoveries in Vermont Geology. 



Orwell, in higher limestones immediately west of and underly- 

 ing the "sparry limestone," there occur Petraia profunda {?), 

 Stenopora fibrosa and St. Peiropolitana, "which may be Birdseye 

 species;" and at the bottom of a hill one and one-half miles 

 northeast of Orwell village, where the "sparry limestone is 

 largely developed," a number of large Maclureas were found 

 (one, as figured in the notes, three inches in its longer diam- 

 eter, and resembling fig. 2 on page 338), which seems to indi- 

 cate the presence of the Chazy limestone beneath the " sparry 

 limestone," or at its base. Higher up toward the top, there 

 are obscure fossils ; but at the top, near the slate, occur distinct 

 bivalves, and the coral Receptaculites Neptuni, which seems to 

 prove the " Sparry limestone" to be Trenton in age. 



In northeastern Shoreham, two miles north of Shoreham 

 village, there is a limestone ledge called Mutton Hill, and here 

 several Lower Silurian formations are distinguishable by their 

 fossils. The rocks, in the words of Mr. Wing, have the follow- 

 ing ascending order : 



1. Light gray even-bedded sandstone, in beds six inches to 

 two or three feet thick ; six or eight feet at the top, honey- 

 combed with Scolithus linearis : Potsdam. 310 feet. 



2. Dark iron-gray, feebly calcareous sandstone or quartzyte, 

 with Fucoids : Upper Potsdam ? 200 feet 



3. Subcrystalline limestone, containing a small Orthoceras 

 and Encrinal disks : Lower Calciferous. 20-25 feet. 



4. Dark greenish, fine-grained sandstone, the lower twelve 

 or fifteen feet perforated with small Scolithi (S. minutus), the 

 rest interstratified with dolomitic limestones, holding Ophileta 

 compacta, 0. complanata, (hence called the Ophi/eta beds), a few 

 other species of convoluted shells including two or three 

 Maclurece, a small Orthis {Orthisina), a Trilobite, etc. : Calcif- 

 erous. 300-400 feet. 



No. 1 is at the western base of Mutton Hill and No. 4 is its 

 geological top. 



In a second fold or anticlinal, Nos. 1, 2, 3 and 4 again come 

 5 _ 8 up; and No. 3 is more than 200 



N 6 ' 7 feet thick and holds a number 



OO° O a °OHi f^^Ti of sma11 Orthocerata, two species 

 ' of Gasteropoda, including a Ma- 

 clurea and a Bathyurus. The 

 mpanving figures by Mr. 

 ^ vv ing serve to sustain his state- 

 ||p 0° OQ ments. Figure 5, an Ort/ioceras 



w apparently the Calciferous spe- 



cies, 0. primigenium; 6, sections of Maclureas : 7, pygidium of 

 a Bathyurus ; 8, shell resembling a Holopea. 



