294 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



We have never heard of the Doolittle being thus affected. Dr. 



Pe^k, a mile north of Croton Station, has a valuable sort of black 



raspberries, which we l^elieve have always been healthy. 



Messrs. Carpenter and Quinn thought the disease came from a 



small red spider. 



Shell IMarl. 



Mr. Almou Whiting, Harmonsburgh, Crawford county, Pa. : 

 "I senct you a specimen of marl which was taken from a bed or 

 deposit of about 50 or 60 acres near this place. It makes excel- 

 lent lime for building purposes when well burned. The marl is 

 about four feet thick, overlaid with peat. This specimen was 

 taken two feet below the surface. At the top of the bed it is in 

 some places composed almost wholly of shells ; the bottom is finer 

 and heavier. Is this the kind of marl used as a fertilizer ? If so, 

 how, and to what soil is it adapted ? I have used it upon wheat 

 and corn, both in the crude state and burned, but find it must be 

 used sparingly, else in hot, dry weather, it burns the crop. I see 

 no difi\3rence in the effect between this and lime. We have m my 

 peat beds in this county, but I know of no other marl. This is at 

 the head of Conneaut Lake." 



The specimen sent is composed of small shells, univalves, which 

 have existed at some period of the earth's history in fresh water 

 ponds and lakes, and are now deposited in masses in various parts 

 of the country. They are not only lime, but lime in a pi'ogressed 

 state, which is, therefore, the more valuable for agricultural pur- 

 poses. Such marl as the specimen sent is worth more per bushel 

 to the farmer than lime made from rocks. It should be vsed in 

 the same way and about the same quantity as you would use 

 slacked lime, and that where it has been used to the best advant- 

 age is applied at about the rate of 30 bushels per acre upon small 

 grain, when it is sown, every three or four years. We have i^ever 

 seen or heard of any soil where lime was not beneficial. If this 

 marl was spread broadcast over Crawford county, it would double 

 the crops in one year. It is one of the beneficent provisions of 

 Providence, who has placed it there for the use of farmers. We 

 are sorry that ignorance should prevent their availing themselves 

 of its use. 



Mr. Baldwin inquired how this marl differed from that known 

 as Squankum marl. 



Dr. Trimble. — It is an entirely different substance. Tliis is 

 nearly all lime, and would answer a good purpose in connection 



