on and near the Erie Canal. ^^ 47 



of the lias rock, after it had lain in a cellar for several weeks. 

 Since that time, specimens taken from a quarry of water 

 limestone on the high ridge between Auburn and Weed's 

 Basin produced the same crystals in the same way. 



12. Calcareous Tufa, or Porous Carbonate of Lime. 



This mineral seems to have been produced by a cause 

 which operated before the deluge, and still continues to ope- 

 rate. The shell marie is adopted by most geologists as the 

 dividing line between antediluvial and postdiluvial deposits. 

 It is in layers, more or less regular, under and alternating 

 with the shell marie, along the canal line throughout almost 

 the whole extent of the great swamp west of Utica. Here 

 it embraces numerous dry-land plants. If its position in re- 

 lation to the shell marie is evidence of its antediluvial charac- 

 ter, these plants are antediluvial, and would furnish valuable 

 materials to aid M. Brongniart in preparing his Antediluvial 

 Botany. But ray doubts on this subject have prevented my 

 sending specimens, agreeably to his request. 



That calcareous tufa is sometimes postdiluvial, and that it 

 resembles the antediluvial kind in all respects, cannot be 

 questioned. About ten miles south of Fort Plain, on the ca- 

 nal, the tufa formation is now going on. I have before me 

 specimens of moss which I collected at that place, with 

 growing tops, while the bases of the stems are entire substi- 

 tutions of tufa. Large logs are now part tufa, and a part 

 decaying wood. Near this place is a cavernous deposit of 

 tufa from ten to forty feet thick, and three or four hundred 

 feet long. It is very difficult to determine whether this is 

 antediluvial or postdiluvial. Another locality of great extent 

 at Elliott's Mills, three miles south of the canal where it 

 crosses Oak-Orchard creek, presents similar appearances, 

 and is still forming. For more particular descriptions of 

 these localities, see Canal Survey, Part 1. 



13. Living Amphibious Animals. 



The discovery of toads in secondary rocks is often an- 

 nounced in public journals. A very particular account was 

 pubhshed inthenewspapers, of one found at Lockport, while 

 they were cutting the canal bed in the geodiferousHme rock. 

 I collected all the facts in my power, and examined the rock 

 from which it was taken. The evidence would have been 

 sufficient to establish any ordinary fact. But there seamed 



