138 QUARTERLY JOURNAL. 



Prof Silliman then observed that the change of level in New- 

 Haven harbor must be owing to other causes than merely the set- 

 ting up of silt, as is generally supposed. 



Mr. Redfield pointed out on the nevv^ chart of New-York bay 

 w^here a few years since there were 40 feet of water, it is now so-< 

 lid shore. This was done by the continual abrasion of the ocean 

 against the bolder shore of Jersey south of Sandy Hook; this was 

 the principal source of supply for making sand bars every where 

 and not what was brought down by rivers from up the country. 



President Dewey said he once heard as a reason for the greal 

 rise of the tides in the Bay of Fundy, that it had a moveable bot* 

 torn (laughter) which sank down very low and in came the tidC' 

 then the bottom swelled up again and out went the tide. He was 

 glad to find that we were turning round properly on a pivot 



The Convention then adjourned till to-morrow at 9. 



[The subject of a change of level in the northern parts of New* 

 York and New-England engaged the attention of the Editor maai 

 years since. In 1834-5, on his w^ay to Nova Scotia, he observei" 

 that the coast in that vicinity was skirted by a deposit of marl; 

 clay in which the remains of moluscous animals of species no\ 

 living in the water were very abundant. The elevation of th 

 formation was stated at the time at forty feet, and the inquiry wa, 

 raised whether this single formation did not indicate a coraparaiil^, 

 tively recent elevation of the coast; it was so regarded at th 

 time, and numerous facts which have since fallen under his obsei 

 vation have confirmed the opinion thus early expressed ; which s 

 far as geologists had then expressed their views, was certain! 

 among the first. Men often express opinions upon a subject, Ion 

 before they are in possession of facts which bear at all upon th 

 subject. In the existence, however, of this deposit so much abov 

 the adjacent water, we have a fact clearly indicating a change ( 

 level at this place. It of course required an extension of the sam 

 fact in order to establish a general rise of the coast. Since thetiiri 

 referred to, many localities have bsen discovered of precisely th 

 same character, as the tertiary of the St. Lawrence basin, whic 

 has been fully described in the reports of the 2d geological diii 

 trict of New-York. See American Journal of Science and Art 

 No. 2, Vol. XXX., the report of 1837. Also final report of th, 

 geology of the 2d district of New-York. J — Ed. 



