Luther — Geology of the Salt District. 



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Westward the proportion of black shale increases in both the upper and 

 lower beds, and the sandy layers diminish in numbers and thickness, and this 

 tendency is manifest from the eastern limit of the district to lake Erie. 



The highest subdivision of the Portage group is the Portage sandstones, 

 which are best exposed and developed immediately above the upper Portage 

 falls, where they are 185 feet thick including twelve feet of hard blue shales 

 in three unequal layers. 



The sandstone is in layers from two to ten feet thick separated by very 

 thin shaly partings. It is light blue-grey when freshly broken, assuming a 

 slightly yellowish tinge after long exposure. 



In a majority of the layers the rock is compact, durable and valuable 

 as building stone, and has been considerably quarried for that purpose in the 

 vicinity of Portage falls, and at Nunda, Castile, Rock Glen and other places. 



At some horizons the sandstone has a laminated or coarsely shaly struc- 

 ture or is soft and blocky. 



Eastward from this locality the formation is less distinctly developed, but 

 whether the change is due to a diminished quantity of sediment or to a differ- 

 ence in the character of the deposits is not as yet definitely established. 



Westward from Portage across Wyoming county the formation is well 

 developed but diminishes rapidly in thickness. It is well exposed in the vicin- 

 ity of Rock Glen at the south end of the Oatka valley, and in the upper part 

 of the ravine west of the village of Varysburg in the Tonawanda creek 

 valley where the beds aggregate seventy feet in thickness. 



The salt wells in the Oatka valley that are located on the rocks of the 

 Portage group are the Globe well, the Pioneer well, the wells of the Crystal 

 Salt Company ; the Miller Salt Company; the Atlantic Salt Company; the 

 Warsaw Salt Company ; the Gouinlock Salt Company; the Hawley Salt Com- 

 pany ; the Empire Salt Company ; the Eldredge Salt Company ; the Kerr Suit 

 Company. Other wells are also located in this group; those at Nunda, 

 Dansville, Livonia, Naples, and Dundee ; the Glen Salt Company's wells at 

 Watkins ; the Ithaca Salt Company's wells at Ithaca, and the Ithaca test 

 well. 



Chemung Group. The shales and sandstones of the Chemung group are 

 the surface rocks over nearly all that part of the state lying south of the line 

 of outcrop of the Portage sandstones. 



The bottom of the group is so far above the salt beds in the eastern part 

 of the salt district, that it may be considered as being for practical purposes 

 beyond its limits. 



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