On the supposed transportation of Rocks. 349 



on the Hudson, and others, to rocks, similar in composition 

 and structure nearest to the place where these bowlders are 

 now observed. Among other loose rocks, a solitary mass 

 weighing several tons, has for a long period attracted the at- 

 tention of our mineralogists. It is, or rather was (for it has 

 now disappeared,) at the corner of Broome and Willet-streets, 

 and is called stellated asbestos, although its real nature has 

 not we believe been fully ascertained. It has been always 

 referred to the serpentine rock at Hoboken, from whence ac- 

 cording to the received theory, it must have been transported 

 by ice across the Hudson river, to its present situation. 



Recently, a bed of serpentine occupying at least twenty 

 acres, and containing the same radiated asbestos, has been 

 discovered on the island nearer to this loose mass. Its greater 

 proximity would then naturally lead us to refer this detached 

 mass, to the newly discovered bed instead of supposing it to 

 have been derived from Hoboken, and subsequently transpor- 

 ted across the river. In a line with the large rock and the 

 bed recently discovered, Mr. I. Cozzens, has pointed out an- 

 other similar mass, about three hundred pounds in weight, 

 near the three mile stone on the middle road. 



Reflecting on these circumstances, I have been led to 

 suppose, that wherever these apparently foreign rocks occur, 

 a careful examination of the surrounding country will in ma- 

 ny cases, prevent us from looking very far from the spot where 

 they are now found. 



Where secondary rocks occur scattered over a primitive 

 country, it is easy to conceive that the original strata of which 

 they formed a part have been in the course of time, disinte- 

 grated and destroyed, leaving a few of the harder portions 

 on the new surface thus exposed. Examples of this sort of 

 destruction of entire strata are numerous. In our own coun- 

 try we need only allude for the present, to a paper by Mr. 

 Barnes in the fifth volume of this Journal, on a geological 

 section of the Canaan mountain. 



Where primitive rocks, on the other hand, are scattered over 

 a secondary or alluvial region, we need not look to primitive 

 mountains several hundred miles distant, in order to find their 

 origin. We know that primitive rocks, frequently thrust 

 themselves through all the superincumbent strata. Now on 

 the supposition that these peaks may have been destroyed 

 by some convulsion of nature, or by the resistless tooth of 

 time, and their origin concealed by the detritus, we can ac- 



