112 
GEOLOGY 
etc. — of which few or none are extinct; indeed, very many of the species differ but little from the 
littoral shells now existing on various parts of the American coasts. 
« In fact , so strikingly different are the fossil reliquiae of the two formations of which we have spoken, 
that it is much to be wondered at that they have ever been considered as contemporaneous , especially 
since the study of fossil conchology has afforded so many additional facilities for collecting and com- 
paring geological facts. In truth, the Secondary and Tertiary formations of America appear to have no 
analogous features ; the former is remarkably homogeneous in its earthy mass , and contains very few 
genera and species of shells , which are all of the Pelagii class. Its fossils , wherever observed , whether in 
New Jersey or in South Carolina, have hitherto been found not only generically, but even specifically 
the same, and there can be no doubt, that, wherever it is penetrated, its productions will be found 
characterized by the same remarkable simplicity. On the contrary,, the shells of the Tertiary, as we 
have remarked above, are vastly abundant in genera and species, all of which are littoral, and disposed 
in a matrix which presents almost every variety of earthy compositions. 
« Alluvial formation. — This consists of two depositions, which may be designated as the Ancient 
and the Modern Alluviahi. 
« The first of these , or the Ancient Alluvial , is chiefly composed of Red earth. This earth is pretty 
uniform in its characters, consisting of sand, with a minute portion of clay, coloured by red oxide of 
iron: its inferior parts often contain pebbles, etc». 
« This deposition occupies the highest elevations above the Secondary and Tertiary classes , and 
consequently could not have been formed by our existing rivers. It is entirely unmixed with the Ter- 
tiary , and destitute of the fossils which characterize the latter ; it must therefore be considered as dis- 
tinct from it, at the same time that it is unlike the modern alluvial, whose origin is clearly attributable 
to the overflow' and inundation of our rivers.# 
« The Alluvial proper, or Modern Alluvial, is well characterized in the Southern States, in consequence 
of its being thrown up against some one of the masses already spoken of, and there appearing as the 
debris of the rivers which traverse those States; the greater part of which, even at this period, contri- 
bute largely to this deposition. The two alluvials of the Northern States are not so well defined, in con- 
sequence of the similarity of their products; for there is groat difficulty in distinguishing even between 
the Ancient Alluvial and the Tertiary in those States where the Red earth is replaced by other matter^ 
unless shells are present. — Finally, it is certain that all the bones of mammoth, and other mammiferous 
terrene quadrupeds found in this region, belong to the two AUuvialsy>. (Extract from Geological Observations 
on the Secondary, Tertiartj , and Alluvial formations of the Atlantic Coast of the United States of America. Arranged from 
the Notes o/’ Lardner Vanuxem, by S. G. Morton. — Road before the Academy of Natural Sciences of Philadelphia, 
January 8, 18J8.) 
Dr. Morton never claimed the honor of being the first discoverer of the Cretaceous formation 
in America; his only merit was the arrangement of the materials collected by Vanuxem; and in a 
note at the foot of the first page of the memoir just cited, Morton says; «The friends of Mr. Va- 
«nuxem are aware that he lately passed a few days in this city (Philadelphia), prior to his em- 
«barkation for Mexico: during that period, his time was so engrossed with preparatory arrange- 
« ments , and with the publication of a chemical essay , that he requested me to arrange the materials 
«of the following papei\ After I had finished the manuscript, we examined it together, and it is now 
« published as corrected by the author. — S. G. M. — January 5, 1828. » 
Morton’s celebrated Synopsis of the Organic Remains of the Cretaceous group of the United States, 
Philadelphia, 1834; begins as follows: a Ferruginous Sand. Mr. Vanuxem was the first to detect the 
« analogy between this deposit and the chalk formation of Europe; etc.» (See page 7.) 
