SECTION ON SANDY CREEK. 349 



Feet, 

 the falls, and 130 feet of strata are shown at the falls and below. The 



strike of the beds at Pulaski and at the falls is nearly the same, and the 



difference of altitude between them is 320 feet. Adding the thickness of 



the exposure at Pulaski to the supposed concealed thickness (320 feet) and 



the thickness at the falls (130 feet), we have 300 



Fossils: This belt is characterized by the upper Lorraine fauna, as 

 represented by the following species : Orthls testudinaria, Modiolopsis 

 modiolaris, Mar chisonia miller i, Cyrtolites ornatus, etc. From the drift 

 blocksof the division there have been collected: Monticulipora discoid V a, 

 M. lens, M. mamillata, M. (2 sp. undet.), Glyptocrinus decadactylus, 

 Leptama sericea, Lingula quadrata, Orthis erratica, 0. biforata, O. oeci ■ 

 dentalis, 0. testudinaria, Bholidops subtruncata, Stropkomena alter nata, 

 S. alternata var. nasuta, S. tenicistriata, Ptilodictya (sp. undet.), Belle- 

 rophon bilobatus, Cyrtolites ornatus, Mxirchisonia bellacincta, M. gracilis. 

 M. milleri, Plenrotomaria subconica, P. trophidophora, Raphistoma len- 

 ticulare, Endoceras (sp. undet.), Orthoceras (4 sp. undet.), Ambonychia 

 radiaia, Avicula demissa, Cleidophorus planulatus, Lyrodesma poststria- 

 tnm, L. pulchellmn, Modiolopsis curta, M. faba, M. nasuta, M. modio- 

 laris, M. pholadiformis, M. truncata, Orthodesma contract urn, 0. paral- 

 lelum, Conchicolites Jtexuosus, Acidaspis (sp. undet.), Asaphus platy- 

 cephalus, Calymene callicephala, and Trinucleus concentric"*. 



5. Gray sandstone 30 



810 



The basal beds of gray sandstone are not seen in continuous outcrop be- 

 tween Salmon river falls and the Medina sandstone. At Fultonville, Oswego 

 county, a well passed through the Medina, and thence through the gray 

 sandstone and Lorraine shales to the Trenton limestone. The record of the 

 well gave: 



Medina sandstone - 

 Lorraine sandstone and shales - 

 Dark shales (Utica) 

 Trenton limestone - 



2,050 " 



This result indicates a thickness of 1,000 feet for the rocks of the Hudson 

 period in northwestern New York, and the measured and estimated Bections 

 give 8104- feet, to which there is to be added the thickness of the sandstone 

 beds beneath the red Medina sandstone. 



Comparing these sections with that of the Hudson valley, they are found 

 to be less than one-third of its thickness ; but they are characterized in the 

 same manner, in the upper portion, by interbedded sandstones and <:ilc:uvoii> 

 sandstones alternating with shales, and in the lower portion by a consider- 

 able development of dark argillaceous shales. Comparing the fauna, \\c find 



