9. 10.DISON township. F*. 259 



The bed a, thoiurh a very calcareous shale in hard solid 

 bur thin layers, yielded no fossils except a doubtful mark 

 or two. 



The bed b is little beside a perfect mass of shells of 

 Lept rditia alta, apparently the same as that occurring at 

 Paterson. Juniata county, (see note.) in the railway cutting 

 through the same shales at that place. The material also 

 of the bed is very much like that of the Paterson bed. 

 The bed c is really the lower part of b but is harder, more 

 brittle, and breaks with a square fracture. It consists, like 

 that above it. of the shells of a Leperditia of the same 

 species apparently. 



The bed d is a hard, dark, close limestone yielding very 

 little except a Leperditia ill preserved but probably the 

 same as that in the beds below it, b and c. 



The Lower Helclerberg limestone, No. VI. 



The northern-central part of this township is occupied 

 by a broad sheet of this limestone thrown into low undula- 

 tions or waves. The erosion of all the overlying strata has 

 exposed this bed, the disintegration of which constitutes a 

 broad hilly district of good fertile land. Four, if not more, 

 of these small anticlines traverse the limestone, producing 

 a constant change of dip, and bringing to the surface dif- 

 ferent beds in different places. 



The Blue Limestone beds. — These beds which form the 

 most valuable material for limestone are well exposed at 

 numerous places. At Adairs' quarry west of Centre about 

 25 feet of this formation can be seen dipping into the hill at 

 20°-25° north-northwest. The lowest beds are the thickest, 

 those above becoming gradually thinner. 



The Slcaly Limestone beds. — These beds — the Premeri- 

 dian Limestone of Rogers — are seldom opened in conse- 

 quence of tlif- nearness of the more solid bed below them. 

 But near Bixler s mills a quarry shows the upper part of 

 theni from the Meristella beds up to the Tentaculite and 

 Flint beds. The usual fossils may be collected here but the 

 exposure is not large. 



A --mall quarry on the roadside, near the house marked 



