632 



FARMERS' REGISTER 



[No. 10 



Cardium, &c. Over these strata is the usual lay- 

 er of ironstone, and the general aspect of the up- 

 per beds is somewhat ferruginous. 



It is interesting to remark, that with some inter- 

 ruptions, a fragmentary deposite, similar to that ob- 

 served at York, extends to the low extremity of the 

 peninsula. At Pocosin, a flat swampy country, 

 which is often inundated by the tides, this deposite 

 is uniformly met with by digging a tew feet below 

 the surface Pectunculus, Pecten, Ostrea, as well as 

 numerous small shells occur mingled with it, as at 

 York; the fragments, however, are not cemented 

 together, but form a loose friable mass. A rock, 

 consisting of cemented fragments of shells, occurs 

 also at various other points on the eastern portion 

 of the Miocene district; and a fragmentary depo- 

 site, like that above described, is found near the 

 extremity of all the peninsulas formed by our 

 great rivers. 



A very interesting feature in the structure of the 

 cliif at York remains to be described. Though 

 the general direction of the fossil beds is nearly 

 horizontal, several of the strata of rock are com- 

 posed of transverse layers parallel to each other, 

 generally dipping towards the north, and making 

 an angle of fifien or twenty degrees with the hori- 

 zon. The course, of these lammse sometimes dif- 

 fers in adjoining strata, and in some places the ob- 

 liquity diminishes gradually until the lamina? be- 

 come, horizontal; thus presenting a remarkable re- 

 semblance to the appearances described by Lyell 

 and others, as existing in the Crag of England. 

 The phenomenon here described, viewed in con- 

 nexion with the fragmentary structure of the rock, 

 and the general distribution of broken shells over 

 the lower extremity ot the peninsula, would seem 

 to indicate the former agency in this district of 

 coast currents and an ocean surf. The beds of 

 shelly matter comminuted by these means, and 

 subsequently elevated above the level of the tide, 

 would be gradually cemented into a rocky mass 

 by the crystallization betweenthe particles of such 

 portions of the calcareous matter, as the rain when 

 just, fallen was capable of dissolving. The solvent 

 power of rain, being chiefly due to a portion of 

 carbonic acid with which it becomes united in its 

 descent through the air, would be lost, as the li- 

 quid percolated through the shelly strata, and thus 

 the calcareous matter which it had seized, would 

 be gradually deposited in the crystalline form. 



Besides shells and Zoophytes, the bones of ce- 

 taceous animals and the teeth of sharks, are of 

 very frequent occurrence in the fossiliferous beds, 

 but no remains of fresh water or land animals 

 have as yet been discovered. The total number 

 of species of shells from these points which have 

 yet been identified, is about ninety-six, to which 

 may now be added several new species recently 

 discovered, and described in a joint paper by Pro- 

 fessor H. D. Rogers and myself. 



The structure of the interesting portion of the 

 state lying on the eastern side of the Chesapeake, 

 is so far, as hitherto explored, extremely simple; 

 but as yet only the. surface strata have been ex- 

 amined, and it is far from being improbable, that 

 at. no very considerable depth beyond that reached 

 by the ordinary wells of the country, deposit es 

 calculated to prove of much economical value, 

 might be attained. Beneath the superficial sands 

 and sandy clays of the country, a bed of clay of a 

 tenacious character is first reached, frequently im- 



pregnated with salt, and communicating to the 

 water obtained from it more or less of a brackish 

 flavor. Beneath this a more arenacious bed oc- 

 curs, beyond which, as far as I can learn, no dig- 

 ging has been carried. From this more sandy 

 stratum, water of a purer quality is procured. 

 Hitherto no beds of marl or fossil shells have been 

 found any where in this region. Yet there is rea- 

 son for the opinion, that such depositee would be 

 met with by boring to some depth, and possibly 

 near enough to ihe surface to prove available in 

 the agriculture of the country. 



The water of the Miocene marl district, wheth- 

 er of wells or springs, presents nearly as great va- 

 riety as the mineral beds from which it issues. In 

 the more eastern parts of the region, it generally 

 contains a notable impregnation of common salt, 

 and in neighborhoods where shell marl abounds, 

 a marked proportion of calcareous matter. The 

 copiousness and transparency of springs of the 

 latter description, as well as the carbonate of lime 

 which they hold dissolved, give them a character 

 nearly allied to that of the limestone springs of 

 other regions, while the common salt which they 

 almost invariably contain, and with which they 

 are sometimes strongly imbued, constitutes an im- 

 portant feature of distinction. The beds of ferru- 

 ginous clay and sand in many cases, impress a 

 a slight chalybeate character upon the water, and 

 occasionally impart to it so large an impregnation 

 of iron as to render it of decidedly medicinal util- 

 ity. 



Owing to the calcareous matter, and occasion- 

 all}' other substances which it holds in solution, 

 nearly all the water of this region possesses the 

 character of hardness. By boiling, this evil is en- 

 tirely remedied; — the carbonate of lime is precipi- 

 tated, first rendering the liquid cloudy, and subse- 

 quently collecting on the sides and bottom of the 

 vessel in the form of a thin incrustation. In such 

 of the arts as require a water free from this pecu- 

 liarity, the marl water should be boiled previous to 

 use; or, in lieu of this, though by no means an ef- 

 fectual substitute, it should be exposed for some 

 time to the sun in open reservoirs. The carbonic 

 acid which is the chief solvent of the calcareous 

 matter, being expelled by heat, suffers the latter 

 to separate from (he liquid, and thus the cause of 

 the hardness of the water is in a great degree re- 

 moved. It is obvious from these facts, that, the 

 water obtained from strata of gravel, sand or pure 

 clay, will in general be purest and most suitable 

 for employment in the arts. As an example of 

 the kind of impregnation usual in the water of 

 this district, I subjoin the results of an analysis of 

 the contents of a spring in James City county, near 

 Williamsburg. In 400 cubic inches of this wa- 

 ter, the aggregate of solid matter was found to 

 be 104.49 grs. consisting of the following sub- 

 stances, viz: 



Muriate of soda, 49.84 



Muriate of lime, 15.08 



Carbonate of lime, 26.73 



Sulphate of lime, 6.24 



Silica and alumina, 4.00 



Sulphate of soda, 0.25 



. Ammonia, a trace, 



Organic matter, 1.00 



Loss, 1.75 



104.49 



