ONONDAGA SALT GROUP. 101 



rock, the hopper-shaped cavities, and other less characteristic masses. In no part of the range 

 is there a vertical section, of any great height, of the gypseous masses exposed ; and there- 

 fore there is no absolute certainty of their being in ranges, and of the number of ranges, 

 though certain localities prove both ; and the disposition of the vsrhole third deposit to a strati- 

 form arrangement favors a like state for the gypsum, but does not define the number of the 

 ranges. 



The next mass in importance to the gypsum geologically, is the Vermicular limerock. 

 This rock is essentially calcareous, and was first made knovm by Prof. Eaton. It is a porous 

 or cellular rock, strongly resembling porous or cellular lava. It derived its name from observ- 

 ing in it " several holes, which were still lined with a kind of tubular calcareous shell or crust, 

 in some measure resembhng the tubular covering of the Serpula, which is so often seen per- 

 forating coral rocks." In color it " is a dark-grey or blue rock, perforated every where vrith 

 curvilinear holes; but very compact between the holes." The holes or cells vary from 

 microscopic to half an inch in diameter ; the cells generally are very irregular, and communi- 

 cate in most instances with one another. Some are spherical, and contain spherical crusts. 

 The resemblance of no small part of the rock to a porous lava is perfect ; but should the cells 

 in lava be caused by gaseous matter as is commonly supposed, these then had a different 

 origin. In Bull's plaster quarry in the town of Lenox, the structure of the cells leave no 

 doubt as to their mineral origin. The cells show that parts of the rock were disposed to sepa- 

 rate into very thin layers which project into the cells, an efiect wholly at variance with aeriform 

 cavities, but evidently the result of the simultaneous forming of the rock, and of a soluble 

 mineral, whose removal caused the cells in question. This view appears to be fully confirm- 

 ed by the discovery in this rock of those forms which are due to common salt, showing that a 

 soluble saline material had existed in it, had acquired shape in the rock, and had subsequently 

 been dissolved, leaving a cavity, or cavities. 



There are two masses of the vermicular rock, an upper and a lower one. The former 

 commences at the ridge west of Oneida creek, and extends to Port Byron. Its thickness is 

 about four feet ; its pores or cavities are usually large. The lower mass is limited, having 

 seen it only on Foot-street road near Syracuse, and in the road which goes from the turn- 

 pike to Bellisle south of the rail-road. Its pores are small, and its greatest thickness is 

 about twenty feet. 



