84 The Saint Peter Sandstone. 



Like that of New York, the formation called Chazy in 

 Canada seems to hold a stratigraphic position comparable 

 to that of the Saint Peter sandstone, and, as Joseph F. 

 James (34, p. 131) has pointed out, it is in a way a trans- 

 ition between the Chazy proper and the Saint Peter, since it 

 is neither chiefly limestone like the former nor pure sandstone 

 like the latter, and since it lies geographically intermediate. 



The Saccharoidal sandstone in Missouri* was believed 

 to be the equivalent of the Saint Peter by Meek, as also by 

 Shumard (loc. cit.), and more particularly by Worthen (12). 

 In fact the Saccharoidal sandstone is lithologically and 

 stratigraphically like the Saint Peter. Mr. Meek found 

 fossils in it, but unfortunately they have never been described. 

 No new' evidence has since been added. Charles R. Keyes 

 has recently doubted that the ** Saccharoidal" sandstone is 

 the representative of the Saint Peter in Missouri, t the latter 

 being, as he thinks, either absent or represented bj^ a lime- 

 stone. He gives no reasons ior this new departure. 



ORIGIN. 



Keating, who was surprised, like many other explorers,, 

 at the purity of the Saint Peter sandstone, mentions some- 

 one's theory ''that this sandstone must have been formed 

 by a chemical precipitation and not by mere mechanical 

 deposition." (See 4, p. 330.) Owen, on the contrary, never 

 mentions anything but sedimentary phenomena in his de- 

 scriptions of the formation. Hall and Whitney (8) adopted 

 the chemical theory to explain the purity, although appar- 

 ently but once. 



The Saint Peter sandstone is a mechanical sediment and 

 consists of quartz grains such as come from the erosion and 

 decomposition of acidic eruptive rocks (see Chamberlin, 26). 

 Its structure is that of a mechanical sediment. It contains 

 marine fossils. One must therefore explain the purity of the 

 stone in some other way than that which explains the purity 

 in salt and gypsum deposits. But no explanation offers 

 itself readily^. 



* See Geological Survey of Missouri, 1st Ann. Rep. (1853) pp. 117 and 197; 

 2nd An. Rep. (1854) pp. 105, 145 and 160. 



t Missouri Geological Survey, vol. 4, pp. 30. 35 and 38. 



