330 Ornithichnology. 



1. Their lithological characters. — De la Beche describes the new 

 red sandstone group, as a " deposit of conglomerate, sandstone and 

 marl, in which limestones occasionally appear in certain terras of the 

 series" — and such a deposit, we have seen, is the sandstone in this 

 valley. 1 have no doubt in respect to any member of this list, unless 

 it be the marl. There occurs here, indeed, a fine red rock, resem- 

 bling the English red marl ; but not usually containing much carbo- 

 nate of lime. It is rather a reddish shale, although it will frequently 

 effervesce with an acid. The variegated aspect of the new red sand- 

 stone, which in some deposits of that rock is so striking, is frequently 

 present along the central parts of the valley, although I should judge, 

 less common, than in Europe. In fine, I can hardly distinguish a 

 suite of specimens from the Connecticut valley, from a suite obtained 

 in Nova Scotia, from a group of rocks proved to be new red sand- 

 stone by containing beds of gypsum. 



2. Their mineral contents. — Excepting a minute quantity of gyp- 

 sum, this rock is wanting in that mineral and rock salt-^and this 

 seems to be the principal difficulty in deciding whether it is the new 

 red sandstone ; since these minerals are so generally present in that 

 forma^tion, and are regarded as characterizing it. But since it is ad- 

 mitted that limestone may occasionally be absent from it, without 

 destroying its geological identity, why may not gypsum and rock 

 salt be sometimes wanting, without taking away its essential charac- 

 teristics ? 



In this rock, however, other minerals occur, that are somewhat 

 peculiar to the new red sandstone. Copper may be mentioned, 

 which is frequently found near the junction of this rock with the 

 greenstone ; and also to some extent disseminated through its lay- 

 ers. In Germany, it is well known that one variety of this group, 

 the copper slate, is wrought as an ore of that metal. The sul- 

 phates of baryta and strontia are found, also, in our rock, as they 

 are in the new red sandstone in England : and the same is true in 

 respect to magnetic iron sand. 



3. Their organic remains. — A few years since, there were found 

 in one of the coarser varieties of this rock in Connecticut, the re- 

 mains of a vertebral animal, of what kind, has never been ascertain- 

 ed. But, as no vertebral animal, except perhaps a few fish, has 

 been found below the new red sandstone, the presumption is, that 

 the rock in the valley of the Connecticut, containing these remains, 

 cannot be older than the new red sandstone. The occurrence of 

 birds, so low down in the rock series, however, contrary to all pre- 



