186 



Scientific Geology. 



as the horizontal distance from one extremity of the cliff to the other, 

 across the strata, is not more than 80 rods, and appears to be merely 

 an insulated remnant of the formation, we cannot be sure that the 

 position of the green sand is near the upper part of the original for- 

 mation. It ought here, also, to be remarked, that the organic remains 

 found in this sand, such as crabs, shells, and alcyonites, are rolled ; 

 and were obviously the ruins of some former rock. Indeed, nodules 

 of a peculiar conglomerate are found in this sand, sometimes con- 

 taining organic remains. 



3. Lignite. As this constitutes beds sometimes as much as five 

 feet thick, it seems deserving of a description among the strata, rather 

 than as an imbedded mineral. It alternates with the clays, princi- 

 pally with the blue variety, with which it is often intimately mixed. 

 More commonly it is comminuted and forms a dark mass, some- 

 what resembling peat. But sometimes the woody fibre is very dis- 

 tinct. In short, it seems like a deposite of peat, through which logs 

 are interspersed. It burns but poorly. The principal beds lie not 

 far from the middle of the cliff, and have a dip from 40° to 50° north. 



4. Conglomerates. The most interesting of these is the osseous 

 conglomerate ; which consists of rounded quartz pebbles, rarely 

 more than an inch in diameter, with a cement of animal matter, (?) 

 clay, iron, and sometimes a minute portion of carbonate of lime. It 

 abounds in fragments, mostly rolled, of the bones and teeth of ani- 

 mals ; some of thetn very large. It is sometimes as hard, and broken 

 with as much difficulty, as gray wacke : but in other places the cohe- 

 rence is not strong. 



The strata of this conglomerate are from one to three or four feet 

 thick, and for some time I supposed that it had been deposited in a 

 small basin on the edges of the elevated strata of clay and sand ; for 

 I found the bed, which I first discovered, to lie as in the following 

 sketch. 



