THICKNESS OF THE LUDLOW FORMATION. 



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ever, make a sufficiently close approximation ; for no one can pass along the banks of 

 the river Teme in the gorge at Downton, without perceiving that the upper Ludlow Rock 

 alone, as interposed between the flaglike junction beds of the Old Red Sandstone near 

 the Tin Mill, and the Aymestry limestone at Downton on the Rock, is many hundred 

 feet thick ; for in proceeding from east to west, the observer rapidly passes over suc- 

 cessive strata, presenting themselves in separate ledges, and rising from beneath each 

 other at gentle angles of inclination. The thickness of the Aymestry limestone is 

 easily calculable, as the whole face of the rock is frequently exposed in one mass. 

 Again, the escarpments of Mocktree Forest, Mary Knoll, &c, afford excellent data for 

 measuring the dimensions of the lower Ludlow Rocks, as lying between the Aymestry 

 and Wenlock limestones, and leave little doubt that this subdivision is quite as thick 

 as the uppermost. We shall not therefore exaggerate in estimating the total thickness 

 of the Ludlow formation at about 1500 feet. 



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