494 MOUND EXPLORATIONS. 



PENNSYLVANIA. 

 VALLEY OF THE JIONONCiAHELA. 



Throughout the valley of tlic ^Moiiougahela liver are abuudaut evi- 

 dences of a former population. iTiclosures, village sites of all the dif- 

 ferent forms, togetiier with numerous (lei)i)sits of mussel shells, bones, 

 pieces of pottery, and other indicia of a settled iwpulation occur fre- 

 quently. From the river bottoms to the tops of the highest hills, rising 

 more than (iOO feet ab'ove the water, these remains are to be seen. At 

 a former time the river flowed at a greater elevation than now, forming 

 a broad terrace known as the " 100-foot level," that being its height 

 above the present bed at Pittsl>urg. Along this level, which for dis- 

 tinction will be called the " upper terrace," seeiiied to be the favorite 

 place of al)ode of the aborigines, as remains of e\ery kind are found 

 more plentifully here than on either the l)ottoms or liill lands. 



Several miles back from the river, in either direction — that is, along 

 the water-sheds between the ( )hio and Monongahela and between the 

 latter and the Youghiogheuy — many mounds are repin-ted, but whether 

 they really exist is a matter f(n' future investigation. 



Within a few miles of Monongaliela are, or have been, a few mounds 

 and not less than fifty stone graves. This refers to the part of the coun- 

 try lying immediately along the river. Of the mounds, only one was 

 found to l)e composed of earth, the others being entirely of stone or 

 of a stone interior covered with earth .How the stone was arranged 

 in them it was (with one exception, to be noted hereafter) impossi- 

 ble to determine. They have been repeatedly disturbed l)y parties who 

 took no note of the structure and could tell nothing more than that " the 

 rock was down at the bottom and the dirt thrown over it." It was only 

 after several days of search and visits to all the localities of which any 

 information could be obtained, along the entire eastern margin of Wash- 

 ington county, that .a few could be found intact. 



On the upper terrace, within the corporate limits of Monongahela 

 city, are situated tlie garden and greenhouses of Mr. I. S. Crall. Two 

 ravines on the east and west sides open directly south into Pigeon 

 creek, and their erosion has lowered the ground until it is surrounded 

 by higher land on every side except along the bluff next to the creek. 

 The further side of the creek being bounded by a high hiU, the view 

 from the level land between the ravines is shut oft' in every direction, 

 except through a narrow i)ass looking up the river; thus the tract is 

 surrounded on every side by hills close at hand, ranging from 40 to 1'50 

 feet above its level. In excavating for foundation walls and other pur- 

 poses, Mr. Crall has, at different times, unearthed skeletons, some of 

 them of large size; the ground is strewn with mussel shells, flint chips, 

 etc. 



