NATURAL SCIENCES OF PHILADELPHIA. 
219 
tains, embracing the head waters of the River Saskatchewan.* To the west, 
from Red River, it extends to and beyond Santa Fe, embracing the head waters 
of the Colorado, and stretching north-west, reaches the head waters of the Co- 
lumbia, as well as those of the Missouri River. Following a south-western 
direction from Red River through Texas, it crosses the Rio G-raude into New 
Leon, and thence south through St. Luis Potosi, it passes indefinitely into Mexico. 
In all the great extent of this formation, there is evidence of the cretaceous 
period^ while most of the species differ from our eastern fauna, as the lithologi- 
cal characters do in the rocks and sediments. 
In New Jersey, the green sand beds are but slightly calcareous, the limestone 
lying above having about 80 per cent, of lime. In North and South Carolina, it is, 
according to Pro. Tuomey, " 25 to 30 per cent, of the mass," but in Alabama it 
is " highly calcareous." 
This vast extent of a simultaneous deposit of this kind, is calculated to excite 
the greatest interest, when we consider how much it affects our agricultural pros- 
perity ; and in a geological point of view, it has received the attention of many 
of our ablest investigators. 
Prof. Vanuxem, in the first place, had in view, the division of McClure's " al- 
luvial," and in his paper he gives a table, dividing it into secondary, tertiary, 
and alluvial. To these he gave seven subdivisions — two only to the secondary, 
No. 1, being "Marl of New Jersey and Delaware," which he refers to the" green 
sand, or chalk of Europe." 
Dr. Morton, in his " Synopsis of Organic Remains," (page 13,) in 1834, six 
years subsequently, gives in a table the same three grand divisions, with a 
difference in the subdivisions, assigning the name of Ferruginous sand" to 
the lower division in which Prof. Vanuxem had continued the name of " Marl 
of New Jersey," the equivalent of" green sand, or chalk of Europe." Subse- 
quently, in June, 1835, in an appendix, page 89, he separates the "Cretaceous 
deposits of America" into three divisions, the " Upper, Media!, and Lower." 
In 1840, Prof. H. D. Rogers published his Report on the Geology of New Jer- 
sey, in which he separated the cretaceous group into five divisions, under the 
name of " the upper secondary series, embracing the green sand formation." 
1. A group of sands and clays, extremely white and pure, 
2. A mixed group, consisting of green sand, alternating with and occasionally 
replaced by layers of a blue, sandy, micaceous clay, the so-called "green sand 
formation. ' 
3. A yellowish, granular limestone, having a profusion of organic remains. 
4. A yellow, very ferruginous coarse sand, with some fossil shells of the 
green sand formation. 
5. A coarse, brown, ferruginous sandstone, sometimes passing into a con- 
glomerate. 
Subsequently, in Johnston's Physical Atlas, 1855, under the name of "Newer 
Mesozoic," he continues these divisions, the whole thickness of which he pre- 
sumes to be a thousand feet. 
Prof. Tuomey, in the tables of his geological survey of South Carolina, in 
1848, calls the New Jersey deposits " upper green sand;" those of South Caro- 
lina, " the gault;" those of Alabama, tbe lower green sand, equivalent to the 
Neocomien of the French geologists. 
In 1854, Messrs. Hall and Meek made a communication to the American 
Academy of Arts and Sciences, on some fossils from the Cretaceous Formation 
of Nebraska. This they divide into five sections. 
5. Arenaceous clay passing into argillo-calcareous sandstone. 
4. Plastic clay, the principal fossiliferous bed of the upper Missouri. 
3. Calcareous marl, containing Ostrea congesta^ &c. 
2. Clay containing few fossils. 
] . Sandstone and clay. 
* See the map of Nebraska, by Lieut. Warren and Dr. Hayden, with explanations by the latter 
who has done so much for the geology of the Western Territories ; also the excellent map of Hall 
k Lesley, in Major Emory's Report on the Mexican Boundary Survey, and Prof. Hall's ]{eport of 
the Geology of the Boundary in the same volume. Also, the various papers of Meek & Hayden . 
1858.] 
