Tracks of Animals in Variegated Sandstone. 259 



are called, " Schalsteinbanke ;" while at Polzig they correspond to 

 the under " Werkbank," and are called the upper " Werkbank." 

 This sandstone formation at Polzig, consists of thinner strata, is 

 firmer, and more gray, on which account it is called, in the upper 

 region, '' Eisenstein ;" but I found no oolite there. 



On these sandstone strata, follows at both places, slate-clay, 

 with one or two sandstone plates intermediate. At Porthen, how- 

 ever, it is colored rather red, than greenish gray, and is there call- 

 ed, "rother Schutt." Upon this, rest the so called, " Sandplat- 

 ten," thin, yellow sandstone strata, which extend over a much 

 larger region at Porthen than at Polzig. 



The slate-clay aud sandstone, finally, which cover these sand 

 plates, occur only in some places in the highest parts of the quar- 

 ries, and in general considerably contorted. 



The engraved plate is not to be regarded as geometrically exact, 

 for the thickness of the layers is only conjectured, and it is in 

 the main, a representative of several contiguous quarries, rather 

 than an accurate copy from one, which appeared to me would be 

 exact enough for the present object. 



I proceeded in a similar manner, with the copies of the foot- 

 tracks : they are sketched, indeed, individually exact, according 

 to their natural size, being even measured with the compasses; 

 but their relative position is arbitrary, they being placed thicker 

 than is usual on the slabs, as the most distinct reliefs of several 

 individual slabs, are united in a small space. Besides, the form 

 in these hasty outlines, may be more sharply marked out, than is 

 really the case in nature, in order to make up for the want of a 

 practiced hand, which alone can represent any thing distinctly, 

 and yet true to nature. These sketches may give an idea of the 

 thing, but a better account may be hoped for, from Professor 

 Rossmassler, for whom I have this day ordered a wagon-load of 

 the large slabs to Freiberg. 



