145 



consequence of numerous nearly parallel anticlinal foldings of 

 the strata, sending promontories or fingers of the older rocks, 

 within the area of the newer or semi-metamorphic, to the west of 

 their average boundary, and causing, of course, corresponding 

 troughs, or synclinal folds of the newer, to enter eastward of the 

 average boundary, the general area of the older. The Atlantic 

 slope has received hitherto so little exact geological study, that 

 we are, as yet, without the data for determining with any 

 precision, either the succession of its much broken and closely- 

 plicated strata, or the geographical limits which separate even 

 the larger sub-groups. It is sufficient, however, for our present 

 purpose, to show the existence and the approximate range of two 

 great metamorphic systems, separated by a physical break ; and 

 the conformable relations of the later or upper of these to well 

 known lower paleozoic formations of the Appalachian chain. 



Mr. T. T. Bouve said he was incredulous as to the 

 matter of slates being so altered as to be mistaken for 

 gneiss or altered into true gneiss ; he questioned whether 

 gneiss ever were a deposited rock. 



Dr. C. T. Jackson made some remarks dissenting from 

 Prof. Rogers upon certain points in the metamorphic 

 theory, and adduced some observations upon the slates 

 of Pequauket Mountain, in New Hampshire, in support 

 of his views. 



Prof. Wm. B. Rogers supported the theory of Prof. H. 

 D. Rogers. 



Dr. T. M. Brewer read the following 



LIST AND DESCRIPTIONS OF EGGS OBTAINED IN CALIFORNIA 

 BY E. SAMUELS. 



Buteo montanus, Nuttall. The Western Red-tailed Hawk or 

 White-throated Buzzard. This bird was first recognized as a 

 distinct species by Mr. Nuttall, (Manual, 1840.) Its claims to 

 this distinction have remained unrecognized until very recently. 

 In the Proceedings of the Philadelphia Academy, Feb. 1856, 



PROCEEDINGS B. S. N. H. — VOL. VI. 10 APRIL, 1857. 



