f 



t 



146 QUARTERLY JOURNAL. 



of the Yellow Springs in Pennsylvania contained silica in solution ; 

 and he thought sufficient attention was not paid to the presence 

 of silica, as he believed it acted a very important part in mineral 

 waters, and he believed it to be soluble in pure water. 



Dr. Jackson thought the solution of silica was owing to the 

 presence of crenic acid ; you cannot separate them. 



Dr. Barrett considered that the presence of shells had a grea 

 effect in purifying water. _ 



Dr. Jackson agreed with this view, and mentioned as an illuS' 

 tration the lime pond in New-Hampshire ; where large quantit^e^ 

 of organic matter were converted into food by shell fish ; they har 

 concentrated the lime in the water— the organic matter mto 

 shell ; and formed a large deposit of shell marl. 



The Convention then adjourned. 



EVENING SESSION. 



The chairman announced the business to be : 



1. Foot tracks in the sandstone of the Connecticut valley, b 



Dr Barrett. 



2. Classification of the animals that made the tracks, by Proi< 



Hitchcock. 



3. New fossil foot tracks in the new red sandstone ol Pennsy 



vania, by Dr. Dean. i -nn 



4. Evidences of the congelation of the new red sandstone, by U\ 

 Barrett. (This paper was deferred.) ^ , , , x-u- 



Dr Barrett said that it was in 1826 he first found tracks ot birc' 

 in the red sandstone of Connecticut, and told Prof. Silhman of i 

 He now would show the track of a new animal, a right and 1 

 foot • the centre toe is a little worn ; I called it a canthodactylua 

 the treading was quite heavy. The next track is that of an ani^ 

 with a tread as heavy as the hippopotamus ; the loot is b inclD 

 in diameter ; part of the second foot is broken. A third speciint 

 comes near the elk or some of the ox tribe. It is evidently tti' 

 of a hoofed animal. It is in pale grey soft sandstone ; and U 

 track is filleil with blue grit. It is in a slab of pavement m the stre 

 of Middletown. The stone is 21 inches wide, and 3 feet 5 inchl 

 lonn- • the tracks are in the middle of the stone ; the foot mari 

 arels inches wide and about the same length ; also the same di 

 tancc to the front of the next step. All the slabs with tracks cap 

 from a quarry one mile west of Middletown, near the comb fa 

 lory They are rare in the Portland quarry ; the one most cOD 

 mon is about 5 inches long, and is unlike any belore knovvn. * 

 thinks the large foot track to be the same animal that Dr. KM 

 described, but his animaPs feet were only half the size He al 

 found foot tracks of birds of a gigantic size, 14 inches ong and 

 inches wide. He also saw tracks of a pair of feet that looked vej 

 much like the human foot, but not quite so long ; he showed 



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