322 ANNUAL OF SCIENTIFIC DISCOVERY. 



at their northern extent in Canada, and had decided that magnesia was 

 present in them in inconsiderable quantity only; and he hud, therefore, pro- 

 posed the name of nacreous schists, instead of talcose. 



ON THE STRATIGRArHICAL POSITION OF THE SANDSTONES OF THE 



CONNECTICUT 111VEU VALLEY. 



In a communication on this subject, made to the American Association 

 for the Promotion of Science, Springfield, 18-39, by Mr. J. D. Whitney, the 

 author stated, that the peculiarity of this sandstone series of rocks in the 

 Connecticut River Valley, was its almost uniform easterly dip, in a direction 

 at right angles to the greatest longitudinal extension of the basin. As re- 

 gards the origin, or cause, of this dip, extended observations on the forma- 

 tion had led him to the following conclusions: 



1st. That it was a physical impossibility that the sandstone should have 

 been deposited in a horizontal position, and then elevated, so as to have its 

 present dip, by the elevation of the metamorphic or so-called " primary " 

 rocks to the west. 2d. That it could not have acquired its present dip from 

 the intrusion of the trap. 3d. It must therefore have been deposited with its 

 present dip, and under the influence of some cause acting with considerable 

 uniformity along the whole extent of the basin. 4th. This agent which pro- 

 duced the deposition of materials with an inclined dip, must have been a 

 more or less violent current setting across the basin, or into it from one side, 

 throughout its whole length. 5th. The cause of this current was to be sought 

 for in a fault running along one side of the basin, followed by a depression 

 of its area, which was greatest on its western edge, and which gradually de- 

 creased in amount towards the east, and which was continued for a consid- 

 erable time, with greater or less regularity. Mr. W. argued that this cause 

 was the only one sufficient to account for all the phenomena, especially those 

 of the dip of the sandstone and the peculiar association of this rock with the 

 trap which no theory yet proposed seemed satisfactorily to dispose of. Lo- 

 cal variations of dip in the vicinity of the trap were allowed to be present, 

 especially in the upper part of the basin ; but the general facts seemed to be 

 better reconciled by the aid of this theory than of any other yet proposed. 



In the discussion which followed, Mr. C. II. Hitchcock dissented from the 

 views of Mr. Whitney, and considered that the delicate footprints existing 

 in these strata proved that they must have been horizontal when in a plastic 

 state. If they had been lying at an angle of 45!, the appearance of the 

 tracks would have been different. 



Mr. Whitney replied, that his views were applicable to the region taken as 

 a whole, and the place where the tracks were found might be an exception, 

 arising from some local cause. 



GEOLOGICAL SUMMARY FOR 1859. 



On Elongated Pebbles in a Conglomerate, at Neirport, R. I. At the Springfield 

 meeting of the American Scientific Association, Prof. Hitchcock called at- 

 tention to the existence of curiously elongated qunrtzose pebbles and trans- 

 verse joints in a conglomerate rock, at the well-known locality, " purga- 

 tory," at Newport, R. I. The pebbles are sometimes elongated to the extent 

 of a foot in length, while their axes are always in the same direction. Joints, 

 or breaks, occur at intervals, which divide both the pebbles and the matrix, 

 as if a clean cut had been made crosswise through the entire mass. Prof. H. 



