160 A CENTUEY OF SCIENCE 



prominence of this hill was due to the erosion of the sedi- 

 ments which once surrounded it. 



An extensive paper on the geology of this region was 

 published by Edward Hitchcock in 1823, 4 then just thirty 

 years of age. This paper shows the evidence of exten- 

 sive field observations, and his comments in regard to 

 the trap and granite are of interest. Hitchcock gives 

 five pages to the subject of " Greenstone Dykes in Old 

 Red Sandstone " (6, 56-60, 1823) and makes the follow- 

 ing statements : 



"Professor Silliman conducted me to an interesting locality 

 of the'se in East-Haven. They occur on the main road from 

 New-Haven to East-Haven, less than half a mile from Tomlin- 

 son's bridge . . . (p. 56). 



They are an interesting feature in our geology, and deserve 

 more attention ; and it is peculiarly fortunate that they should 

 be situated so near a geological school and the first mineral 

 cabinet in our country . . . (p. 58). 



Origin of Greenstone. 



Does the greenstone of the Connecticut afford evidence in 

 favour of the Wernerian or of the Huttonian theory of its 

 origin? Averse as I feel to taking a side in this controversy, I 

 cannot but say, that the man who maintains, in its length and 

 breadth, the original hypothesis of Werner in regard to the 

 aqueous deposition of trap, will find it for his interest, if he 

 wishes to keep clear of doubts, not to follow the example of 

 D'Aubuisson, by going forth to examine the greenstone of this 

 region, lest, like that geologist, he should be compelled, not only 

 to abandon his theory, but to write a book against it. Indeed, 

 when surveying particular portions of this rock, I have some- 

 times thought Bakewell did not much exaggerate when he said 

 in regard to Werner's hypothesis, that, 'it is hardly possible 

 for the human mind to invent a system more repugnant to 

 existing facts/ 



On the other hand, the Huttonian would doubtless have his 

 heart gladdened, and his faith strengthened by a survey of the 

 greater part of this rock. As he looked at the dikes of the old 

 red sandstone, he would almost see the melted rock forcing its 

 way through the fissures ; and when he came to the amygdaloi- 

 dal, especially to that variety which resembles lava, he might 

 even be tempted to apply his thermometer to it, in the suspicion 

 that it was not yet quite cool . . . (p. 59). 



By treating the subject in this manner I mean no disrespect 

 to any of the distinguished men who have adopted either side of 



