Description of the Latrobe Quadrangle
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DESCRIPTION OF THE LATROBE QUADRANGLE By Marius B. Campbell. HARMON, WESTMORELAND COUNTY. direction of Chicago, and a minor fold from the GENERAL RELATIONS. PHYSIOGKAPHY. [Latitude 40° 19' 47.78". Longitude 79° 26' 19.91".] western end of Lake Erie joins the major axis near APPALACHIAN PROVINCE. Position and area. By reference to the key map In Unity Township about 3 miles north of west of the type locality. From Cincinnati the anticline on the cover of the folio it will be seen that this Latrobe, on a high ridge known locally as Dry Eidge. In its physiographic and geologic relations this passes due south to Lexington, Ky., and there quadrangle is located in the Conemaugh Valley in The ridge is flat on top and the station is near the cen quadrangle forms a part of the Appalachian prov curves to the southwest, parallel with the Appa ter of a cleared field. western Pennsylvania. That part of the territory ince which extends from the Atlantic Coastal Plain lachian Valley, as far as Nashville, Tenn. Its lying north of the river embraces the southwestern MARSHALL, WESTMORELAND COUNTY. on the east to the Mississippi lowland on the west, maximum development is in the vicinity of Lex part of Indiana County and in it are located the [Latitude 40° 27' 32.39". Longitude 79° 25' 08.15".] and from central Alabama northward beyond the ington, where the Trenton limestone is exposed at towns of Blairsville, Saltsburg, and Tunnelton; the In Loyalhanna Township, about 3J miles southwest of boundary of the United States. the surface at an altitude of 1000 feet above sea Saltsburg, on the highest part of a bare, flat hill, which level; but in Tennessee it again swells into a dome area south of the river, which is by far the larger SUBDIVISION OF APPALACHIAN PROVINCE. part of the quadrangle, is in Westmorland County is the southwestern one of three hills that stand near like structure which is represented togographically together. The land is owned by Mrs. William Marshall. and includes the towns of Latrobe, Bradenville, With respect to topography and geologic struc by the Central Basin of Tennessee. Deny, Millwood, Liverrnore, New Alexandria, STROBLE, WESTMORELAND COUNTY. ture the Appalachian province may be divided into This anticline ..separates the Allegheny Plateaus Georges Station, and various mining towns that [Latitude 40° 17' 11.77". Longitude 79° 29' 51.34".] two nearly equal parts by a line which follows the into two structural basins, which are best known have sprung up in the vicinity of the larger coal About 4 miles southeast of Greensburg, on a cleared Allegheny Front through Pennsylvania, Maryland, by the coal fields that they contain. The western mines. The most important town south of the ridge having timber on its western end. There is a and West Virginia, and the eastern escarpment of basin extends far beyond the limit of the province river is Latrobe, from which, on account of its size higher summit 1 mile eastward. The laud is owned by the Cumberland Plateau across Virginia, Tennessee, and contains the Eastern Interior coal field of Illi John Stroble. and central location, the quadrangle has been Georgia, and Alabama (see fig. 2). nois, Indiana, and Kentucky. The eastern basin named. The area of the quadrangle is 227.6 STEELE, WESTMORELAND COUNTY. East of this line the rocks are greatly disturbed lies entirely within the limits of the Allegheny square miles. [Latitude 40° 29' 00.34". Longitude 79° 31' 34.73".] by faults and folds, and in many places they are so Plateaus and is generally known as the Appalach Triangulation stations. The exact latitude and About 4 miles west of Saltsburg, on the southern part metamorphosed that their original characters can be ian coal field. By reference to the map, fig. 42, longitude of the boundaries of the quadrangle of the summit of a high, bare hill in Bell Township, on determined with difficulty. West of the dividing illustrations sheet, it will be seen that the Latrobe land owned by John Steele. (latitude, 40° 15-40° 30'; longitude, 79° 15-79° quadrangle is situated in this basin, near its northern 30') have been determined from stations located TABERNACLE, INDIANA COUNTY. extremity. A more detailed description is neces upon some of the most prominent hilltops of the [Latitude 40° 30' 51.57". Longitude 79° 21' 49.71".] sary in order to convey a thorough understanding region. These have been connected by triangula- About one-half mile east of Clarksburg post-office and of the local geology and topography. tion with astronomical stations at Washington, about 6 miles by road north of Sallsburg, on the highest Since the Appalachian coal field is a structural part of a bare cultivated round-top hill o\vued by the basin or trough, the strata around its margin gen D. C., Cumberland, Md., Grafton, W. Va., and heirs of S. "W. Coleinan. Pittsburg, Pa., and the accuracy of the work has erally dip toward the center of the field. This is been checked by a carefully measured base line ROSE, WESTMORELAND COUNTY. particularly noticeable on the two sides, the rocks ' ' along the Pennsylvania Railroad on the eastern [Latitude 40° 23' 03.83". Longitude 79° 41' 36.25".] on the northwestern side dipping gently but regu margin of the quadrangle (see Bull. U. S. Geol. About 4 miles north of Irwin, on a cleared ridge larly to the southeast and those of the southeastern owned by the Eose heirs. Survey No. 181). side dipping more strongly to the northwest. In All surveys for the maps of this folio are based Level lines. The.general altitude and configu Pennsylvania and West Virginia the regularity of upon six triangulation stations located within the ration of the surface of the quadrangle is shown the dip on the southeastern limb of the trough is quadrangle and four other stations in close prox by means of contour lines which are based upon interrupted by parallel folds which, where hard imity thereto. Each station is marked by a stone precise levels run by the Pennsylvania Railroad FIG. 2. Diagram of northern portion of the Appalachian rocks are involved, give rise to anticlinal ridges and province showing physiographic divisions. post set firmly in the ground, on the top of which engineers and by the United States Geological Sur synclinal valleys. These undulations are similar is cemented a bronze tablet marked "U. S. G;eo- vey. During the course of this work numerous line the rocks are entirely unaltered; they lie nearly to the great folds east of the Allegheny Front, logical Survey-Pennsylvania." The accompany bench marks were established (see Bull. U. S. flat, and the few folds which break the regularity except that they are developed on a very much ing diagram (fig. 1) shows the relative positions of Geol. Survey No. 185). of the structure are so broad and open that they smaller scale and have not been broken by faults produce scarcely an appreciable effect. as have many of the folds farther east. Across the Bench marks in the Latrobe quadrangle. HILTY TABERNACLE The general topographic features are well illus northern extremity of the basin, where the rocks Feet above sea level. (1903 adjustment.) trated by fig. 41, illustration sheet, which is a are nearly flat, there are a great many of these STEELE Blairsville, Pennsylvania Railroad pas relief map of the northern part of the province. minor folds, which extend south west ward at least senger station, northeast corner of, The plateau which constitutes most of the north half way across Pennsylvania from its northern on foundation offset (Pennsylvania ( Railroad bench mark No. 60), chiseled western part of the State is bounded on the south boundary. In the southern part of the State there square................................ 1,011.909 east by a sharp escarpment which extends from are only six pronounced anticlines, and two of these Blairsville, Walnut Street Bridge; northeast wing, wall of, on coping Williamsport, in the north central part of the disappear near the West Virginia line. Farther stone, aluminum, tablet marked "1008 State, to the head of Potomac River, in western south the number is reduced, until on Kanawha PITTSBURG-"....................... 1,003.077 Maryland. This escarpment, which is known as River the regular westward dip is interrupted by Blairsville, Maple'' street crossing, top of rail at....... ......... ........... 1,010. the Allegheny Front, is a great dividing line only one or two small folds. Georges station, overhead bridge, on between the principal geologic as well as the Drainage. Most of the surface water of the north pier of, aluminum tablet marked "1199 PITTSBURG"........ 1,199.180 physiographic divisions of the State. Allegheny Plateaus finds its way into the Missis Latrobe high school building; alumi East of this line the surface consists of alter sippi, but that which drains the northeastern end num tablet marked "1026 PITTS nating ridges and valleys, as shown in the Greater flows either northwestward into the Great Lakes or FIG. 1. Sketch map showing location of triangulation sta BURG" .............................. 1,026.206 tions on which the survey of the Latrobe quadrange is Livermore, 0.25 miles north of; at inter Appalachian Valley, and of a slightly dissected southeastward through Susquehanna, Delaware, based. section of roads, on rock, chiseled upland like the Piedmont Plain of eastern North and Hudson rivers into the Atlantic Ocean. mark................................. 932.89 these stations, and the following descriptions will Livermore, at north side of; covered Carolina and Virginia. West of the dividing line The arrangement of the drainage lines in the enable engineers to identify them on the ground. bridge over Conemaugh River, north the surface is composed of more or less elevated northern part of the province is largely due to the end of...............................