OP STRATA, 



41 



careous, when it approaches the character of limestone. On Water 

 burning and mixing, as in the manufacture of mason^s mortar, l^^^e'^ooe. 

 it becomes a solid cement under water. 



Localities, It extends along the stage road from about 30 

 miles west of Utica to near Genesee river ; a distance of 

 about 130 miles— also at Lockport. Contents. Gypsum and Gypsum, 

 the vermicular limestone are found in beds in this rock and in 

 no other. All may be seen at JManlius Centre, along the 

 south bank of the canal. Shell limcctone is common in this 

 stratum. One of the best localities is between the lower 

 Genesee Fall and the one next above it, on the west side. 



Shell grit is generally reposed on the upper surfice of the 

 lias. But it belongs to the quartzose formation of the third 

 series. See the profile section on the map and the synopsis. 



16. Geodtferotjs Limerock, consists of carbonate of lime, 3. Calcare- 

 combined with a small proportion of argillite or quartz in a 

 compact state, mostly foetid, and always containing numerous 

 geodes. Subdivisions. Stvinestone, when it contains very 

 little or no quartzose sand, is irregular in structure, foetid and 

 abounds in geodes. Sandy, when it contains quartzose sand, 

 is stratified, scarcely foetid, and contains but few geodes. 



Localities. Swincstone is found in the bed and banks of Fetid, or 

 the Erie canal near Genesee river, and extending one mile 

 east. The canal at Lockport it cut through this rock to the 

 depth of nearly thirty feet, for two miles. It forms the upper 

 part of Niagara Falls to the depth of seventy feet. The sandy 

 division overlays the swinestone. Its characters are well ex- 

 hibited at Black Rock, immediately under the cornitiferous 

 limerock. Here it contains malachite and magnesia, as con- Contains 



^ . ^, 1 • 1 1 • • magnesia 



stituents. Specimens ot this rock, r.tter lying a year m a and copper, 

 damp cellar, shoot out numerous crystals of Epsom salts. — 

 Varieties. The fetid can scarcely be considered a distinct 

 variety. The darker the colour, the more fetid the odor. 

 Contents. The geodes contain sidphate of sirontian, granu- in'geodes. 



