244 



GEOLOGY OF THE THIRD DISTRICT. 



Scratches and Furrows upon Water-worn Rocks. 



The worn surfaces of rocks, and the scratches in determinate directions which they often 

 present, are now an interesting subject of geological inquiry, in the greater part of all North- 

 ern Europe and in this country. One of the best localities in the third district for observing 

 these phenomena, is at the limestone quarry of Mr. Marcellus, commonly called Schelpin- 

 town, situated about two and a half miles to the northeast of Amsterdam. The surface of 

 the rock is covered with soil and earth, which, when removed, show a water-worn surface 

 with two or three sets of scratches, exhibiting great regularity, and having a common direc- 

 tion towards the east, one set of which is about eight degrees south. The scratches, includ- 

 ing furrows, were generally from a mere hue to one-fourth of an inch wide, and from one to 

 two-tenths of an inch and more in depth. 



specimen from Maralius' quarry. 



Ho. 1, hat no parallel on the specimen : It is evidently of an older date than some of the others. 



2. This, with 3 and 4, belong to the same set. It shows tlie effect, when examined, of a tremulous morement. 



3. Lilies which are slight, and some of them not continuous through the specimen. 



4. This exhibits finely the effect of the vibratory movement, and resembles lace. 



5. is a scratch of an older data : It passes under, or is crossed by No. 4. 



6. Part of No. 2, magnified to show the tremulous motion which produced a succession of fine nicks. 



