A geography of Pennsylvania : containing an account of the history, geographical features, soil, climate, geology, botany, zoology, population, education, government, finances, productions, trade, railroads, canals &c. of the state : with a separate description of each county, and questions for the convenience of teachers : to which is appended, a travellers' guide, or table of distances on the principal rail road, canal and stage routes in the state, Part 5

Author: Trego, Charles B., 1794-1874; Marian S. Carson Collection (Library of Congress) DLC
Publication date: 1843
Publisher: Philadelphia : Edward C. Biddle
Number of Pages: 430


USA > Pennsylvania > A geography of Pennsylvania : containing an account of the history, geographical features, soil, climate, geology, botany, zoology, population, education, government, finances, productions, trade, railroads, canals &c. of the state : with a separate description of each county, and questions for the convenience of teachers : to which is appended, a travellers' guide, or table of distances on the principal rail road, canal and stage routes in the state > Part 5


Note: The text from this book was generated using artificial intelligence so there may be some errors. The full pages can be found on Archive.org (link on the Part 1 page).


Part 1 | Part 2 | Part 3 | Part 4 | Part 5 | Part 6 | Part 7 | Part 8 | Part 9 | Part 10 | Part 11 | Part 12 | Part 13 | Part 14 | Part 15 | Part 16 | Part 17 | Part 18 | Part 19 | Part 20 | Part 21 | Part 22 | Part 23 | Part 24 | Part 25 | Part 26 | Part 27 | Part 28 | Part 29 | Part 30 | Part 31 | Part 32 | Part 33 | Part 34 | Part 35 | Part 36 | Part 37 | Part 38 | Part 39 | Part 40 | Part 41 | Part 42 | Part 43 | Part 44 | Part 45 | Part 46 | Part 47 | Part 48 | Part 49 | Part 50 | Part 51


In summer the prevailing winds are from the southwest, and at most seasons this may be seen to be the direction of the upper currents of air by observing the motion of the highest clouds in the atmosphere. In July and August thunder showers are common after a few days of intensely hot weather; when these fail to occur periods of drought sometimes ensue which are very injurious to the summer crops, and in some parts of the State occasion a scarcity of water in the wells and springs.


During the rapid thaws of spring the wind is generally from the south or southeast, which brings us a warm current of air from the Gulf stream, passing along our coast from the Gulf of Mexico northward. A sudden dissolution of the snow then takes place, which frequently causes destructive floods in the streams. A strong and continued south wind in the winter sometimes pro- duces this effect in those parts of the State nearest the ocean. In January 1841, the Delaware and Lehigh were so swelled by the sudden melting of the snow as to sweep away most of the bridges across them, besides destroying many miles of canal along both rivers and carrying away an immense amount of lumber, buildings and other property on their banks.


What is the general character of our climate ? By what cause is it sup- posed to have been somewhat changed ? What other effect may have been produced by clearing off the timber, and why ? Is the climate affected by the elevation of the country ? In what months do the extremes of heat and cold usually occur ? What is said of the winter and spring seasons in the southeastern and southwestern counties ? In the northern and more ele- vated parts of the state ? Of the summer in this region ? Which is the most pleasant season, and what is said of it? Mention the course of the prevailing winds in winter. In summer. When are thunder showers most common ? What frequently produces rapid thaws in spring ? What is the consequence of the sudden melting of deep snows? When and where did a destructive flood occur from this cause ?


6. GEOLOGY.


THE limits and design of a work like the present will prevent us from giving more than a mere general sketch of the highly in- teresting and varied geological features of Pennsylvania. Some of the more minute details, as well as an account of the ores. min- erals, coals, &c., will be given when we come to a description of the separate counties.


4*


42


GEOGRAPHY OF PENNSYLVANIA.


The various geological formations which we shall describe, are composed of successive strata or layers of rock, one resting upon another, from the primary or lowest in the series, up to the rocks containing the anthracite and bituminous coal, which are the highest in the regular ascending order found in the State. If rocks more recent than the coal occur, they occupy only limited areas, where they have been deposited since the formation of that vast system of lower secondary strata which occupy nearly the whole of our territory.


It will be seen by the most superficial observer, in travelling through Pennsylvania, that the course or range of the various groups and beds of rock is in a direction nearly northeast and southwest ; corresponding with the course of the mountain ridges which extend through the State. If he attends to the position of the strata, or various layers of rock, he will see that their horizontal inclination is by no means the same in different places, and that they vary by every degree of slope, from level to perpendicular. This slope or inclination is called by geologists the dip of the rock, and is of great importance in determining the order of superpo- sition.


The stratified rocks of the secondary series being sedimentary, formed by a succession of deposits from water, we must suppose that originally they lay in nearly a horizontal position. The stand- ing and tranquil waters deposited mud at their bottom, which hardened by pressure and by drying, aided, perhaps, by internal heat, at length became slate, or shale ; or if calcareous became a limestone : waters in gentle motion left sand only beneath them, which finally cementing formed sandstones, fine or coarse, accor- ding to the velocity of the current; while streams or tides in rapid motion carried away most of the sand, leaving a mass of pebbles at the bottom, which at last, by the same great solidifying process of nature, became coarse conglomerates. This process of deposits from tranquil waters and different currents, varying in endless suc- cession through indefinite periods of time, would naturally pro- duce the variety of strata which constitute our whole system of sedimentary rocks. The varieties of colour are owing, generally, to different proportions and modifications of the oxides of iron and other metals. In order to account for the different degrees of inclination, or slope, which we observe in the strata, we must im- agine a series of uplifting actions from central forces, similar to the volcano or the earthquake, moving in a direction from north- east to southwest, upheaving the great mountain ridges, breaking up the strata from their former nearly horizontal position, and heaving and tilting them into the variety of disturbed positions in which they are now found.


The southeastern portion of Pennsylvania, including the southern part of Bucks and Montgomery, the whole of Phila- delphia and Delaware, with the southern portions of Chester, Lancaster, and York counties, is occupied by rocks belonging to the stratified primary class. These consist chiefly of gneiss, mica slate, talc slate, and their subordinate varieties : the unstratified


43


GEOLOGY.


rocks of a crystalline structure, such as granite, sienite, &c., being found in small local and irregular veins, principally in the southern portion of the primary range. The primary rocks extend on the Delaware river from Trenton downwards to the southern boundary of the State, and along it westward to the southeastern part of Adams county. Northward of this triangular primary belt is the limestone of Chester and Montgomery counties, which is more or less crystalline, sometimes being marble, and which is also referred to the primary class. Still northward of this limestone, we find in some places a considerable extent of gneiss, with talc and mica slate.


Proceeding farther northward, we come to the red sandstone for- mation, which stretches across the State from the Delaware river above Trenton, to the Maryland line, passing through the counties of Bucks, Montgomery, Chester, Berks, Lancaster, Dauphin, York and Adams. This group of rocks has been referred to the middle secondary period, and is of remarkable uniformity with regard to its materials and appearance throughout its whole range. It .consists of dark reddish brown argillaceous sandstone, soft crumbling red and brown shales, with occasional bands of con- glomerate, or sandstone containing rounded pebbles. The dip, or inclination of the strata is almost always to the northward, descending at an angle of from twelve to twenty-five degrees.


The conglomerates of this group, by which is meant those layers containing imbedded pebbles, are chiefly found in the lower strata along the southern margin of the formation, or in the very highest, along its northern border. In both these cases, where the red sandstone overlies an older limestone in the vicinity, we find that a large proportion, sometimes nearly the whole, of the imbedded pebbles consists of rounded fragments of limestone of various colours. The paste too, by which they are cemented together, is so highly calcareous that the whole mass may be burned into tolerably good lime. Many portions of this conglo- merate, if polished, would make a very beautiful variegated marble, of the breccia variety. The famous Potomac marble, from which were formed the columns in the Representative Chamber of the Capitol at Washington, is of this character and belongs to this formation. It may be seen in Pennsylvania at several points along the northern border of the red sandstone, in the upper part of Bucks and the southern part of Berks, particu- larly near the Schuylkill two or three miles below Reading. It is also found on Yellow Breeches creek in the northern part of York county, and in Adams, near Millerstown or Fairfield, eight miles southwest of Gettysburg.


The red sandstone formation is traversed by numerous ridges and dykes of trap rock or greenstone, which sometimes forms hills of considerable height, and which have usually the same northeast and southwest direction as the other elevated ranges of hill and mountain in the State. This rock is generally of a dark gray colour, with some shade of green, crystalline in its structure, being composed chiefly of feldspar and hornblende, more or less


44


GEOGRAPHY OF PENNSYLVANIA.


closely mixed, and though rather tough and difficult to break, it is frequently used as a material for building. It is, however, seldom quarried for that purpose, being usually found in irregular masses of all sizes, scattered over the surface and in the soil. This rock is evidently of igneous origin, and having been brought to the surface in a state of fusion, being upheaved through the dislocated beds of red sandstone in a highly heated state, it has frequently changed the texture and colour of the shale and sand- stone in its neighbourhood, converting them into a baked hard blue rock, totally different from their original character. In some of the ridges which cross the upper part of Bucks and Mont- gomery counties, the hard blue altered rock only is visible, the trap having never reached the surface ; but its heat from beneath has been sufficient to change the colour and texture of the over- lying shales and sandstones. The soil of these ridges is generally wet clayey and cold, and but little esteemed for purposes of agri- culture, while the soil of the unaltered red shale and sandstone is fertile and productive.


North of the middle secondary red sandstone last described, we find on the Delaware below Easton another belt of primary rocks, which forms a chain of hills stretching southwestward across Northampton, Lehigh, Berks, Lancaster, York, Cumberland, Adams and Franklin counties to the Maryland line. This range is commonly called the South mountain, and though somewhat irregular and sometimes interrupted, may be said to be nearly continuous across the state. Proceeding southwestward along this ridge, we find the primary rocks disappear as we approach the Schuylkill, and though seen occasionally west of that river, they are generally covered throughout the remainder of the range to the Maryland line, by the overlying rocks of the lower secondary series.


That vast system of lower secondary strata which extends from the primary rocks upward to the carboniferous or coal bearing series, has been divided for convenience into thirteen separate groups or formations, which we shall notice in their ascending order.


[. Overlying the primary rocks is a hard, white, compact sand- stone, almost purely silicious, and sometimes exhibiting evidence of the heating agency of the rocks beneath by its excessive hard- ness, its ringing sound when struck, its splintery fracture, and occasional discolouration. This rock is chiefly found along the range of the South mountain, from the Lehigh near Allentown to the Maryland line, near which it is finely exposed on the ex- cavations of the Gettysburg railroad. It is also beautifully seen in the cliffs at Chicques Ridge, on the Susquehanna, above Columbia.


II. Above the sandstone last mentioned is a broad belt of lime- stone, which may be traced from the Delaware river, at and above Easton, through Northampton, Lehigh, Berks, Lebanon, Dauphin, Cumberland and Franklin counties, and so passing southwestward through Maryland and Virginia. Another divi-


45


GEOLOGY.


sion of this formation is seen in the middle townships of Lancas- ter and York counties, extending southwestward into Adams, where it terminates in a point near Littlestown. The same lime- stone is found in many of the valleys in the interior of the state, in the counties of Centre, Mifflin, Huntingdon and Bedford, particularly in Morrison's Cove, Kishicoquillas, Nittany and Brush valleys. This rock is usually of a bluish colour, some- times gray, or nearly black, tolerably pure in general, some of its layers yielding excellent lime, and others containing different pro- portions of sand, clay and oxide of iron. It frequently also con- tains bands and nodules of chert, usually called flint, which is generally of a dark colour. Fossil shells and zoophytes are abundant in some portions of this formation. Iron ore is also frequently found in the soil above it, and many of the most pro- ductive ore banks in the State are within the range of this lime- stone, or immediately on its border. The soil is highly fertile and some of the finest agricultural districts of the State are situated upon this formation.


III. The rock next in order as overlying the limestone is a slate, usually black or bluish, though sometimes gray, olive, or yel- lowish. In some portions of its range through Berks and Lebanon counties, it is red and brown, with some interposed bands of yel- low. It also contains interstratified beds of sandstone, some of which contain rounded pebbles, forming a true conglomerate. Some layers of this formation in the neighbourhood of the Dela- ware and Lehigh yield excellent roofing slate. Hydraulic cement is also made from some of the lower strata next to the limestone. This rock is found extending on the Delaware from opposite Bel- videre to the base of the Kittatiny or Blue mountain at the Dela- ware Water Gap. Thence ranging southwestward between the limestone belt and the mountain, it crosses Northampton, Lehigh, Berks, Lebanon, Dauphin, Cumberland and Franklin, to the southern line of the state. The position of this slate being next above the great limestone, and between it and the sandstone next to be described as usually forming a mountain ridge, it follows that the slate will always be found near the foot of the mountain, or between it and the limestone. Hence, in the valleys through- out the state, where this limestone exists, we usually observe the slate near the base of the mountain, and frequently extending some distance up its side, when not covered or obscured by earth or stones fallen from the mountain itself.


IV. Next above the slate, and dipping conformably with it, is a formation composed of massive strata of hard white and gray, or sometimes reddish or greenish silicious sandstones of various de- grees of coarseness, frequently containing pebbles of considerable size. This rock constitutes that long, narrow, nearly level and continuous ridge which stretches from near the Hudson river, not far from Kingston, across New York and New Jersey, and which, entering Pennsylvania at the Delaware Water Gap, is known from that place to its termination in Franklin county, by the name of Kittatiny or Blue mountain.


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GEOGRAPHY OF PENNSYLVANIA.


This formation is also recognised in many of the high and rug- ged sandstone ridges which are found in the counties of Juniata, Mifflin, Centre, Huntingdon and Bedford. In its numerous windings, foldings and irregular convolutions, it forms the moun- tains called Tuscarora, Cove, Shade, Jack's, Brush, Nittany, White Deer, Bald Eagle, Will's, the long complicated range called the Seven Mountains, and some others. It is also seen in Montour's Ridge, from near Bloomsburg in Columbia county to the West branch of Susquehanna, five miles above Northum- berland.


V. Resting upon the sandstone last described, and generally near the base of the mountain ridges which contain it, is a series of red and variegated shales, containing in its lower portion some strata of red sandstone, and usually towards the upper, some thin layers of argillaceous limestone. This group, consisting mainly of soft argillaceous and calcareous shales, is exceedingly variable in colour, being striped with narrow bands of red, yellow, green, olive and purple. Its character also varies somewhat in different districts of the State ; for while in its long range along the northern side of the Blue mountain we find it almost uniformly to consist of strata of red shales and sandstones, and nearly or quite desti- tute of the thin limestone bands ; yet in other regions of the State it maintains its character of variegated colour and its thin layers of limestone. This formation is important as containing the ex- cellent fossiliferous iron ore which is now extensively worked in the neighbourhood of Danville and Catawissa, in Columbia county, also in several places near the Juniata, and in other parts of the State where this formation occurs. The position of the ore strata is generally found to be in that portion of the formation which contains the thin limestone layers.


This group of rocks lies on both sides of Montour's Ridge north of Danville, and thence stretches across the West branch into Union county. It will also be found in many of the valleys at the base of the mountains which contain the last described sandstone, and if this sandstone forms an anticlinal axis, or arch, in the mountain, dipping both ways from the top, like the roof of a house, the shales of this formation, with their contained ore, being above the sandstone, will be found on both sides of the mountain. This is the case in Montour's Ridge, Will's, Jack's (south of the Juniata river,) Shade and Tuscarora mountains towards the north. If, on the con- trary, the sandstone strata of the mountain all dip in one direc- tion, as in the Bald Eagle or Muncy mountain, the shales of this formation, with their contained ore, will only be found on the side toward which the strata of mountain rock descend, the other being occupied by the slate which has been described as underly- ing the mountain sandstone. It may, however, sometimes occur that the sandstone rocks form a synclinal axis, or trough shaped basin, by dipping both ways towards the centre, as in the Nittany mountain. In this case the valleys on both sides will be occupied by the underlying black slate formation ; while the red and varie- gated shales, being always in position superior to the sandstone,


47


GEOLOGY.


if found at all, will be in the basin above it, near the middle of the ridge.


VI. Next in position above the red and variegated shale forma- tion last described, we have an argillaceous blue limestone, rather slaty, of moderate thickness, though vastly inferior in this respect to that described in Article II. It frequently contains between its layers thin bands of slaty shale, somewhat similar to those of the formation below it; but in its upper portion these disappear and the limestone becomes purer. Some of the strata contain abun- dance of fossil organic remains, commonly called petrifactions, and iron ore is sometimes found associated with it. This lime- stone is found in the valley north of the Blue mountain, above the red shale, and of course north of it, and may be seen at various points along its range, being quarried in many places for use. It is also found encircling Montour's Ridge, outside of the red shale, and extending northeastward nearly to Berwick. In Perry county it sweeps around two large triangular areas, from the Sus- quehanna near Fishing creek, along the northern side of the Blue mountain towards Landisburg, where it folds back and runs north- ward and northeastward beyond Bloomfield. Here it again turns westward towards the head of Sherman's creek, where it again folds round to the northeast, and crossing the Juniata near Millers- town, extends by Pfoutz's valley to the Susquehanna below George- town. In Juniata, Mifflin and Union counties this limestone will be found overlying the red and variegated shales of the last described formation, in the valleys near the Tuscarora, Shade and Jack's mountains, frequently forming limestone ridges which rise above the general level of the valleys. In Huntingdon county it is seen on the Juniata river on the west side of Warrior ridge, and thence extends east of Tussey's mountain, through Bedford county, to the Maryland line. The limestone of the valley about the town of Bedford, also belongs to this formation. The most northwest- ward range of this rock in Pennsylvania is found along the valley of the West branch of Susquehanna, from Muncy, by Williams- port, to the mouth of Bald Eagle creek, and thence up the valley of that stream southwestward to the neighbourhood of Hollidays- burg, on the Juniata. Here it sweeps around south of Brush mountain, and passes west of Canoe mountain, Dunning's and Will's mountain, through Bedford county to the Potomac river, above Cumberland.


This limestone is also found in many other places ; we have only noted some of its principal ranges, as a minute description of all the various windings and doublings of this and other formations would far exceed the limits to which we are confined in such a book as this. Enough has, perhaps, been said to enable the in- telligent and careful observer to distinguish this limestone group from the lower one described in Article II., and which, it will be seen, occupies a very different position in the great series of Penn- sylvania rocks.


VII. The formation next in the ascending order above the lime- stone last described, is of very variable thickness, and in some places


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GEOGRAPHY OF PENNSYLVANIA.


seems entirely to disappear. It is a coarse grained and rather loosely cemented sandstone, of a whitish, or rather yellowish white colour, having in some of its beds abundance of fossil shells, and also some bands of chert or flint; but is not important either for its extent or its mineral contents. Neither is it always con- tinuous in its range with the adjoining formations; for though when found it is always above the limestone last described, and below the olive slate next to be noticed ; yet as has been observed, it is sometimes absent, and the slate which belongs above it is found resting upon the limestone. This is the case in Columbia and Northumberland counties, around Montour's ridge, and per- 1 haps, in some other places.


Where this sandstone is observed in considerable thickness, it generally forms a line of irregular, sharp, rugged hills, such as may be observed ranging southwestward from near Stroudsburg in Monroe county, nearly parallel with the Blue mountain, and ex- tending beyond the Susquehanna into Perry county. It will be generally found accompanying the limestone along its ranges, as mentioned in the preceding article, through the counties of Perry, Juniata, Mifflin, Union, Huntingdon and Bedford. The cele- brated " pulpit rocks," on Warrior ridge, above Huntingdon, be-


Pulpit Rocks on Warrior Ridge.


Long to this sandstone. Some iron ore is found within the range of this formation, and the rock itself is said to form a good mate- rial for the hearths and inwalls of furnaces.


VIII. We now come to a group of alternating strata of dark gray, greenish, and olive coloured slates, interstratified with gray and greenish argillaceous sandstones : the slates predominating


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GEOLOGY.


in the lower beds, where we sometimes also find thin layers of limestone. Some of these lower strata are well adapted for making hydraulic cement. As we ascend in this group the sandstones become more prevalent in the upper portion. Many of the strata in this formation are abundant in fossil shells, encrinites, trilobites, &c. Iron ore has occasionally been found accompanying this group of rocks, but in general it is much inferior in this respect to the lower formations. This group is of much greater thickness than the two last described, and considered in conjunction with the following, both together occupy no inconsiderable portion of territory. When the rock strata are nearly horizontal, or have a gentle dip, a thick group or formation will of course spread over a wide extent of country. But when the strata have been up- heaved into a position more approaching to perpendicular, the area occupied is more confined and narrow. Thus a series of rocks three thousand feet thick, standing in perpendicular strata, would cover about half a mile in width, while the same series if lying nearly flat or horizontal might spread over many miles. Accordingly where we see these two formations on the Susquehanna, between the Kitattiny and the Second mountains, they seem to occupy but little space because the strata are nearly perpendicular ; but fol- lowing them eastward towards the Delaware we find them flatten- ing out to a very gentle northwestern dip, and covering a large portion of Monroe, Pike and Wayne counties. The same remarks will also apply to these and other formations, in various parts of the state.


IX. Above the olive slate formation last described, we find a series of brownish red shales and sandstones, with some inter- posed layers of greenish gray and buff coloured sandstones and shales. This group differs from that last described more in colour than in actual composition; and like it is a broad heavy series of rocks, and extensive in its range. Its sandstones yield abundance of excellent material for building ; but its mineral contents are of little importance. The soil of this, as well as that of the preceding formation, is but moderately fertile; and yet the industrious farmer, by proper attention to the use of lime and other manures, manages to reap a rich crop from the hills of these slates and sandstones.




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