280 BULLETIN OF THE 



to the same conclusion (Nova Scotia, 1848-1868) ; it was adopted by 

 Lyell in i)art (Mass., 1842), and fully by Leconte (1878) and Walling 

 (Mass., 1878). These authors agreed with those of the preceding group 

 in believing that the tilting of the sandstones was the effect of some 

 external force. 



The trap was considered passively intrusive, and the dip of the sand- 

 stone was looked on as the result of original oblique deposition, by H. D. 

 Rogers (Pa., N. J., 1839), W. B. Rogers (Va., 1840), Mather (N. Y., 

 1843), Silliman Jr. (Conn., 1844), and Whelpley (Conn., 1845). 



The former anticlinal connection of the two sandstone strips in North 

 Carolina was suggested by Kerr in 1874, and extended by Bradley in 

 1876 to the Connecticut and New Jersey areas. Russell independently 

 made the same suggestion for the latter in 1878. 



The trap has been considered a metamorphosed sedimentary deposit 

 by Wurtz and Martin (N. J., N. Y., 1870). 



Plate I. may be taken as a pictorial supplement, in illustration of 

 the preceding abstracts. It embraces nearly all the sections that have 

 been drawn showing the Triassic traps within their sandstones. These 

 drawings are not fac-similes, but in the small changes that have been 

 made I think no injustice has been done. 



1. Hitchcock (a). Across the Connecticut Valley in Northern Mas- 

 sachusetts. The vertical position of the gi-eenstone intersecting the 

 strata of Deerfield Mountain was corrected in his next article (6), but 

 in the mean time it had served Cooper as an argument for the igneous 

 origin of floetz-trap. 



2. Hitchcock (6). East Haven (Conn.) dikes ; their sides are too 

 regular and parallel. See our figure 44. 



3. Eaton (c). Across the Connecticut Valley in Northern ]\Iassachu- 

 setts ; excessively wrong. 



4. Smith. Across the Connecticut Valley ; sandstone tilted by the 

 trap, which rose through chasms and overflowed at the surface. 



5. Jackson and Alger (b). Southeastern side of Bay of Fundy. 



6. Hitchcock (c, 221). Across the Connecticut Valley in Northern 

 Massachusetts. 



7. Id. (c, 423). Turner's Falls on the Connecticut in Northern Mas- 

 sachusetts. The increased thickness of the main trap sheet at the sur- 

 foce is wrong. 



8. Chapin (105). Across a number of ridges at Wallingford in 

 Southern Connecticut. The author failed to observe any interbedded 

 sheets. 



