1 1 I ONTARIO DIVISION. 



ridges : hence it is. so far as even] acerned, a good agricultural district. Streams 



which t roes it, cut through the softer portions, and form impassable m inea si gorges ; but 

 these an- not bo frequent as to interfere with farming operations. 



'ii u-hy this roch should be studied. This rock forms an interesting chapter in the bis- 

 torj of the pro<rres* of geology in ihis State. It was considered bj the early cultivators of 

 this science as identical with the New Red Sandstone of Europe, which overlies the Coal 

 measures, that embrace the rock salt of the district of Cheshire in England. Hence these 

 opinions led to speculations and explorations both for salt and coal, underlaid by this rock. 

 This erroneous view arose from placing too much reliance upon Lithologkal characters ; 

 for, in this particular, it closely resembles some portions of the New Red Bandstone. Mr. 

 Conrad and Mr. Vahttxkm, however, were aide, by the character of the fossils, to set this 

 matter right in the first year of the survey. 



Springs originating in (he .Medina sandstone. Brine springs issue from the lower part of 

 this sandstone, hut the water is too impure for the manufacture of salt. The fact is im- 

 portant in a geological point of view, as furnishing a high probability that it is from the 

 chemical changes which the materials undergo, that salt is formed, the elements of which 



- in the body of the rock. As in most instances of mineral springs in Western New- 

 York, the chloride of sodium is adulterated with the chlorides of calcium and magnesium. 



Gcolog-ical relations of the Medina sa?idstone. This rock is succeeded in the ascending 

 order bj the green shales of the Clinton group. Below, it reposes upon the gray sand- 

 stone of Oswego county, which is equivalent to, and identical with, the gray thick-bedded 

 sandstone of the Hudson-river series. It is wanting in the southeastern part of the State. 

 In the rallies of the Hudson and Rondout, the Hudson-river series supports the shales of 

 the Waterlime series (See PI. XXI. Sec. 1 ; and PI. XX. Sec. 3). 



§ 2. Clinton group. 

 The most interesting feature in this group, consists in the rapid changes in the strata 

 which enter into its formation, and which, taken together, constitute a most heterogeneous 

 of materials : for this reason, the group was called, in an early stage of the 

 survey, the Protean group. The formation consists of layers and beds, composed of green, 

 blue, and brown sandy and argillaceous shales, alternating with greenish brown sand- 

 stones and conglomerates, or pebbly beds, rind oolitic iron ore. These different kinds of 

 materials rapidly succeed each other. The late Mr. Eaton called this formation firriferous 

 riferous sandrock. 

 The parts of this formation which are the most persistent, arc the green shales ; whose 

 color, however, inclines more to blue than green, where they have not been exposed to 

 i ndstone, which is rather harsh, in consequence of the predominance 



of sharp angular grains, is also greenish, or greenish gray. The layers of this part of the 

 rock are never thick-bedded, or massive ; and their lower surfaces are often covered with 

 cylindrical bodies, varying in size from a barleycorn to that of the finger. These bodies 



