50 Notice of Hayden's Geological Essays. 



instances, be formed, (possibly,) by decomposition of the 

 angular portions of a stone, by various chemical agencies, 

 aiding those of a mechanical nature, but an immense num- 

 ber, and in our view, the immensely greater number of peb- 

 bles, present unquestionable evidence of having been brought 

 to their rounded form by attrition. 



The attrition of the common waters of the earth, and 

 even that exerted during the comparatively short period of 

 the prevalence of the deluge of Noah, would do very little 

 towards producing so mighty a result, and we must assign 

 this operation to the more recent periods of the prevalence 

 of the great chaotic deluge, whose existence is distinctly 

 recorded in the first chaptei of Genesis, and equally ad- 

 mitted by all geologists. However strongly inclined, we 

 have neither time nor room to pursue this fruitful topic any 

 further, but must leave it to return to Mr. Hayden's book. 



In support of the opinion, that our alluvial formations 

 have been produced by currents, the author mentions " the 

 wave-like or undulating appearance of almost every section 

 of alluvial formation, whether perpendicular to the surface, 

 or inclined, shewing the operation of a current from the 

 north-east." 



This appearance we have often observed in the alluvial 

 plain of New-Haven, and in other alluvial regions of Con- 

 necticut — exhibiting frequently, a delicacy of flexion, in the 

 layers of gravel and sand, which makes them appear as if 

 they had, but a moment before, received their impulse and 

 position from undulating water, and as if they had copied 

 the very eddies, and gyrations of the wave. 



To support the position, that the currents flowed from the 

 north-east to the south-west, Mr. Hayden mentions the riv- 

 ers in the vicinity of Baltimore, which generally run in a 

 direction from north to south. " In almost every instance," 

 he remarks, " where the rolled pebbles abound, they are 

 in much the greatest quantities on the west or south-west 

 side of the river or creek." He states also, that there are 

 great accumulations cf sand and gravel in such places as 

 correspond with the southern mouths or outlets of valleys 

 and streams, or with their southern sides, and but small por 

 tions or none of these things are found in the opposite di- 

 rections. 



