FARMERS' REGISTER-GREEN SAND AND CALCAREOUS MARL. 749 



cases, an enormous accumulation of organic re- ) 

 mains had been discovered. A minute examina- I 

 tion of these remains, consisting of shells, the 1 

 bones of animals, &c., disclosed the curious liict 

 that they belonged to races of beings of which, at 

 present, there are only a very few living represen- 

 tations. Subsequent observations, first systemati- 

 cally made by Cuvier and Brogniart in tlie vicini- 

 ty ol' Paris, turiher demonstrated that overlying 

 the secondary tormation of that region, there ex- 

 isted an extensive series ol" deposites of great 

 thickness, the Ibssil contents of which were, on 

 the whole, very dissimilar from tliose of the form- 

 er — not only all the species, but many of the most 

 remarkable animal and vegetable forms being dis- 

 tinct, while at the same time many of the species 

 were observed to be identical with others now alive. 

 The difference thus marked between the two se- 

 ries of deposites, unitbrmly prevailing wherever 

 they were observed, led to the introduction of the 

 term tertiary, to designate the upper and more re- 

 cent, liy scrutinizing in detail the tertiary series, 

 it was soon discovered to consist of several dis- 

 tinct subordinate formations, characterized by pe- 

 culiar fossils, and becoming more assimilated in 

 their organic contents to the existing living world, 

 in proportion as tlieir position in the series ajj- 

 proached nearer and nearer to the surface, Tlie 

 most recent systematic writer on geology, and one 

 of the most learned and able geologists of the 

 day, has distinguished tour subordinate ibrniations 

 in tfie tertiary series — and has given to each a 

 specific name, expressive of its relative period of 

 deposition. Tliough u.'\wiiling to perj)Iex the 

 reader with the terms of science, I may perhaps 

 be excused on this occasion ibr introducing the 

 names here referred to, on the ground that tliey 

 are likely to be met with frequently hereafter in 

 geological descriptions of the tertiary deposites of 

 this country — and as they are distinctive of things 

 which are characteristically different, and which 

 Uave received no other denominations soajjpropri- 

 ate, they have a just claim to be received. The 

 terms thus employed by Mr. Lyell, the distin- 

 guished geologist above alluded to, are — 



Jst. Pliocene, signifying more recent, and di- 

 vided into newer and older Pliocene. Under this 

 head are comprised some of the shell deposites 

 near the mouths of our rivers. 



2nd. Miocene, signifying less recent. To this 

 formation belong most of our calcareous strata 

 which have previously been referred to under the 

 title of middle tertiary. 



3rd. Eocene, signifying the dawn; indicating 

 the presence of a few Ibssils analogous to living 

 (species, or in other words a dawning of that condi- 

 tion of the animated Avorld which now prevails. 

 Examples of this are furnished in the lower ter- 

 tiary of Alabama, and the lower tertiary here al- 

 luded to as recently discovered in Virginia. 



The nature of the materials in which the fossils 

 of these different deposites are embedded is very 

 various. Sometimes the formation is a soft sand 

 or clay — sometimes a sandstone or limestone ol' 

 comparative hardness. In some cases the deposi- 

 tion appears, from the nature of the fossils, to have 

 been made beneath the ocean— sometimes at the 

 bottom of an extensive lake. In the vicinity of i 

 Paris, there are three marine formations alter- ' 

 gating with two of li-esh water or lake origin; and ; 

 from one of the latter, the celebrated gypsum or ; 



plaster of Paris is extensively quarried. In Virgi- 

 nia, no traces of a fresh water tertiary- have as yet 

 been discerned. The general direction of the 

 deposite is hoiizontal, and the whole appears to 

 have been formed at successive eras beneath the 

 waters of the ocean. 



From what has now been said, it will at once 

 appear that strong features of resemblance are 

 presented in the geology even of the more recent 

 formations in this country and Europe. The most 

 striking similarity exists between the secondary of 

 New Jersey and' that of the Paris basin — as far 

 as fossil contents are concerned. But in Paris, a 

 great proportion of these fossils are embedded in 

 chalk; whereas, in Now Jersey, no chalk has been 

 discovered, and its place is occupied by green sand, 

 very similar to that, which, in the former localitj-, 

 alternates with the layers of chalk. 



The lower tertiary or eocene of Virginia is found 

 in a band of variable, and as yet unascertained, 

 breadth, traversing the state nearly in a direction 

 (rom north to south. It makes its appearance on 

 both sides of the Potomac, in a line a little east of 

 Fredericksburg. It then crosses the Rappahan- 

 nock near Port Royal, the Pamunkey probably 

 near Piping Tree, and the Jam.es River at Coggin'g 

 Point. With regard to its course further south, 

 though its existence is known, additional data are 

 required. 



In general character, this formation may be thus 

 described. At the base of the clilT or bank, there 

 usually exists a stratum of what at first sight ap- 

 pears to be a blue or black clay, but which,"on fur- 

 ther examination, is found to consist principally of 

 particles of the silicate of iron and potash, w^liich 

 when dried, becomes of a Hvely green color. 

 Mingled with this substance are portions of com- 

 mon clay and sand, and numerous minute shining 

 scales of mica. Embedded in the mass, and usu- 

 ally in a very friable condition, numerous shells 

 chiefly of small dimensions will be Ibund. Some- 

 times however, the matter of the shell has entirely 

 disappeared, leaving a distinct cast or impression 

 in the earth, by which its specific character may 

 often be ascertained. Immediately above this 

 stratum is a heavy deposite of what INIr. Ruffin 

 has described as gypseous earth.* Large masses 

 of crystalized gypsum, and sometimes the most 

 beautiful groups of perfect crystals of this sub- 

 stance, are disseminated throughout this layer. It 

 was this portion of the formation which Mr. Ruf- 

 fin conceived to be identical with the green sand 

 of New Jersey. In color, this stratum varies 



* The term "gj-pseous earth," used in the article re- 

 ferred to above, was applied not to a part, (as here sup- 

 posed,) but to the whole of that formation which Mr. 

 Rogers has since shown to be of "green sand." But 

 it was also stated, that by the general application of 

 that term to the extensive beds which seemed to have 

 had a common origin, (and formerly, the same chemi- 

 cal composition,) it was not intended to convey the 

 opinion that all this earth contained sulphate of lime, 

 either in crystals or finely divided. On the confrarj-, 

 that ingredient was said not to be present, in any per- 

 ceptible quantity, in but very few parts of the great 

 body of what was there called "gypseous earth." — Se^ 

 Farmers' Rogist-^r, Vol. I. p. 2nS. — Ed. 



