2g8 



SCIENCE. 



[Vol. XXII. No. 565 



where are we to look for their sources ? Are they due to 

 the destruction of the syenites of Arkansas or the basaltic 

 outbreaks of which Pilot Knob is a representative, or must 

 they be traced to a still more remote source amon^ the 

 eruptive and intrusive rocks of western or central Texas 

 through the media of the Cretaceous, Carboniferous and 

 other stages found in Texas'? 



Another question may be asked. The Tertiary deposits 

 themselves give strong evidences of their being mostly of 

 marine deposition, having throughout the greater portion 

 of them a marine fauna. Had this condition of deposition 

 anything to do with the quantities of soda found in the 

 beds? Was it deposited from the waters of the sea and 

 afterwards absorbed by the clays ? Sodium chloride ap- 

 pears as an efflorescence in many portions of the area. 

 Sodium occurs both as chloride and sulphate in nearly 

 the whole of the mineral waters examined, and even the 

 Greensand marls of the marine beds show, with but few 

 exceptions, a large percentage of soda over the potash. 



The few soils examined by the officers of the Geological 

 Survey have also the same apparent constitution. Soda 

 appears to exceed the potash. 



It may also be of interest to find that, according to Dit- 

 mar, the relation of soda (Na, O) to potash (K^ 0) in ocean 

 water is 100 to 3.23, and in kelp, according to Richardson, 

 100 to 5.26. 



For geological purposes, the Texas Survey has divided 

 the Tertiary deposits into five divisions, which may be 

 briefiy described, in ascending order, as follows: 



First: The basal beds or Wills Point clays — This is a 

 series of blue, bluish gray, yellow and brownish yellow 

 clays, and gray, yellow and brown sands. These clays 

 contain numerous small nodules of calcareous material, 

 and crystals of selenite also occur in places. They also 

 appear as fossiliferous in places. Boulders of fossiliferous 

 limestones, with veins of calcite through them, occur 

 scattered throughout the beds, although the heaviest 

 proportion belong to the yellow-sand division — and 

 occasional irregular deposits of heavy bedded white and 

 grayish white highly fossiliferous limestones form a por- 

 tion of these basal beds. These deposits lie immediately 

 upon the marly deposits of the Upper Cretaceous, and 

 may be said to have been deposited in small bay-like in- 

 dentations along the Cretaceous shore line, or probably 

 have suffered extensive erosion, as they now occur only as 

 isolated patches in a few places along the Cretaceous 

 border. 



Second: The lignitic beds. — These deposits form the 

 lowest portion of Dr. Penrose's Timber Belt beds and 

 comprise a series of blue, brown, yellow, white and gray 

 clays and sands, with extensive deposits of brown coal 

 and lignite. The clays occur as thinly laminated, or strati- 

 fied and massive, sometimes nearly free from sand; but 

 the greater portion occurs as sandy or micaceous clays. 

 Near the base these deposits consist of blue sands and 

 clays, with occasional beds of gray and pinkish white or 

 gray clays and thin deposits of brown sandstones. At the 

 top they become a series of thinly-laminated and thinly- 

 stratified red and white sands and clays, the laminae or 

 strata usually not exceeding % to yi inch in thickness, 

 although the white-clay strata occasionally form beds 

 from four to six feet in thickness. These, however, are 

 very irregular, and when such a thickness of clay occurs 

 it generally forms a pocket-like deposit extending over 

 but a small area. The intermediate beds may be said to 

 be blue and dark gray sands, clays and lignites — the lig- 

 nites often attaining a thickness of from six to sixteen, 

 and even more, feet. These lignite beds are probably the 

 most extensively developed Tertiary deposits within that 

 portion of the coastal plain in the State. Nor are they 

 confined to Texas alone, but occur farther east in both 



Arkansas and Louisiana. In the northeastern portion of 

 the State they have a known thickness of 1,000 feet, wells 

 bored in that region from 800 to 1,000 feet having failed 

 to pierce them; and at Mineola, in Wood County, the base 

 of these beds was not reached in a well 1,200 feet in 

 depth. These beds contain vast deposits of clays of all 

 sorts, including plastic potters' clay and refractory clays 

 showing an analysis equal to the best Stourbridge, as well 

 as clays suitable for the manufacture of the finest grades 

 of porcelain. 



Third: The Marine beds. — Succeeding the lignitic 

 beds and overlying them in direct continuity comes a 

 series of sands, clays and iron ores, the greater portion of 

 which is highly fossiliferous, containing in many places 

 an abundant marine fauna. These beds have an aggre- 

 gate thickness of over 600 feet. Abundant deposits of 

 limonite and greensand marls occur throughout them, 

 but the clays are generally poor and very irregularly de- 

 posited. 



Fourth: The Yegua beds. — The fourth great division 

 has been called the "Yegua clays" from their development 

 on the river of that name. These clays form the base of Dr. 

 Penrose's Fayette Beds, and the division comprises a 

 series of dark blue and gray clays and brown and gray 

 sands and sandy clays, with great quantities of selenite in 

 crystals from nearly six inches in length down to sizes 

 almost microscopic. The water found in these beds is 

 strongly saline, and in many fiortions of the area under- 

 laid by them, especially where the dark blue clays ap- 

 proach the surface, the gray overlying sands show patches 

 of saline efflorescence. Many of the gray clays belonging 

 to this series contain leaves and stems of plants, and 

 heavy deposits of lignites also occur at many places 

 within the same area. 



Fifth: The Fayette Sands. — This division has been 

 called the Fayette Sands chiefly on account of its being 

 made up largely of gray sands and sandstones, although, 

 however, it contains many deposits of very fine white and 

 gray clays, many of which when washed showing decided 

 kaoliuitic conditions. These dej^osits are also more or 

 less fossiliferous, showing at places a scanty marine fauna 

 of the Eocene series, and closely connecting them with 

 the yellow and brown sands of the marine beds already 

 referred to. In the sands belonging to this division great 

 quantities of beautifully opalized wood occur. Beds of a 

 very fine white silicious earth or sinter occur at several 

 places within this area, and the enormous quantities of 

 gray sandstone used at Galveston and Sabine Pass for 

 jetty purposes are obtained from these beds. Many of 

 the claj'S and coarse sandstones belonging to the upper 

 portion of the Fayette beds are highly calcareous, and in 

 places show small quantities of well-worn Cretaceous 

 shells. 



Overlying the Fayette sands there appears a series of 

 heavy-bedded, blue, red, green and yellow and sometimes 

 white clays, with brown and grayish white sands contain- 

 ing small patches of pink clay. These are pretty generally 

 ascribed to the Tertiary age, but their exact position is as 

 yet a matter of doubt. The blue clays contain an abund- 

 ance of calcareous nodules scattered throughout them, 

 although these nodules appear to be wanting in the im- 

 mediately underlj'ing red clays, and are not very plentiful 

 in the overlying yellow and green deposits. These de- 

 posits have not yet received a specific name. They have 

 been described in the Third Annual Report of the Survey 

 under the title of the Fleming beds. Since then, how- 

 ever, more extended research has been made in these 

 beds in southwestern Texas, and Mr. Dumble proposes 

 to assign to the whole division the name of " Frio Clays. " 



The last division of our clay deposits is known as the 

 Coastal Clays. These occupy an area of from 75 to 100 



