IGNEOUS ORIGIN OF LIMESTONE. 41 



tliat I conceived it much nearer to an unstratified mass, than to one which is stratified. And 

 then, those instances, in which it is so clearly an unstratified rock, are so numerous, that it 

 appears better to consider the rock as one belonging to the latter class ; for at best, the ap- 

 pearances of stratification are very obscure, and not at all satisfactory, being nothing more 

 than what often appears in rocks decidedly igneous, as greenstone, basalt and trap. 



It is not to be inferred from the preceding remarks, that the observations of Prof. Hitchcock 

 are undervalued, or may be set aside for slight reasons ; for his long experience as an observer 

 places htm in the fiurst rank as a geologist, and the cause of difference between us arises from 

 his not having on his part an opportunity for observation in the same field with myself ; for I 

 have no doubt but oiir views of this rock would coincide, if St. Lawrrence and Essex coun- 

 ties were made the field for his observations. It appears, however, tlial other geologists ; 

 entertain the same ideas of this rock. Thus, Prof. Daubeny appears to entertain the same 

 views of metamorphism in the following passage* : " A blue limestone stratum is said to 

 " overlie tlie primary or crystalline above mentioned ; and tins has undergone a very remark- 

 " able conversion, near the line of contact, into a white marble, spangled over with minute 

 " specks of anthracite, just the same has happened to tlie limestone of New-Jersey." Again, 

 speaking of the geology of Orange countyt : " The next remarkable circumstance relative 

 " to the beds, is the conversion of the ordinary blue limestone into white crystalline marble, 

 " when it approaches the gneiss ; this limestone contains in all no less than forty-three spe- 

 " cies of minerals." 



The first passage cited is a description of a locality which has often been examined under 

 the most favorable circumstances, and with an express reference to the point now under ex- 

 amination ; and so far from being an overlying mass, it is one enclosed in hornblende and 

 gneiss, in a mode precisely similar to the limestone at Long pond. 



As it regards the latter passage, it is sufficient to remark, that it is the same limestone 

 which is so abundant in St. Lawrence and Essex counties, and which contains also the same 

 minerals in an equal, if not greater abundance. But those masses are never overlying, but 

 are embraced in the primary rocks ; and from observations which I was able to make in the 

 county of Orange, several years since, they, too, are never overlying masses, but are enclosed 

 like the limestone of the north ; and hence, there is no possibility of conceiving how they can 

 be placed in the class of altered rocks. ■ . •. . 



Again, Mr. Redfield, in his account of the exploring visits to the sources of the Hudson, 

 has expressed similar views in relation to a mass of Imiestone at Port Hemy. He says, 

 " The remainder of the day, and a part of the fourteenth, were spent in exploring the vicinity, 

 " and examining the interesting sections which are here exliibited of the junction of the pri- 

 " mary rocks with the transition series, near the western borders of the lake ; and we noticed 

 " with peculiar interest the effect which appears to have been produced by the former upon 



* See Sketches of the Geology of North America, by Prof. Daubeny, p. 28. t Sketches, 4c. p. 52. 



Geol. 2d Dist. 6 



