CLEVELAND MORAINE. 621 



Crooked Creek, and nowhere east from it are more than two members 

 developed. 



Drift knolls abound opposite Hartstown, on the east side of Crooked 

 Creek, near the head of the stream. They apparently correspond in age to 

 those in the Shenango Valley at Jamestown. There is a nearly continuous 

 line of knolls from Hartstown northwest to Pennline, along the east side of 

 Pymatuniiig Swamp, at a right angle to the general trend of the moraine 

 and in about the same direction that the ice moved. It is probably a con- 

 necting link between the southern and northern members of the morainic 

 system. At the time the earliest member of this series was forming the ice 

 sheet apparently stood at Hartstown, on the valley of Crooked Creek; at 

 Jamestown, on the Shenango, and near the line of Ashtabula and Trumbull 

 counties, Ohio, on the Pymatuning. These points mark the southern border 

 of the features in these valleys. At the time the latest member was forming 

 the ice sheet apparently stood at the head of Pymatuning Creek, in eastern 

 Ohio, and at the northwest end of Pymatuning Swamp, in western Penn- 

 sylvania, and the knolls along' this swamp ap^iear to have been formed in 

 connectioii with the retreat of the ice sheet from Hartstown to Pennline, 

 i. e., from the southeast to the northwest end of the swamp. 



The upland between the Pymatuning' Swamp and the valley in which 

 Conneaut Creek and Conneaut Lake are situated has scarcely any drift 

 knolls worthy of note, but along the Conneaut Valley there is a line of 

 di'ift knolls aboiit as long as that on the Pymatuning Swamp, 10 to 12 miles. 

 The southei'n end is east of Conneaut Lake, and the northern end near 

 Conueautville, Pa. The formation of this line apparently occupied an 

 interval of time similar to that between the formation of the southern and 

 northern members of the moraine in the valleys west from here, the south- 

 ern end having been deposited when the ice stood at Hartstown and James- 

 town, Pa., and the northern when it stood at Pemaline, Pa. 



On the uplands between the Conneaut Valley and the Cussewago, two 

 feeble moraines were observed, one passing from the southern end of 

 Conneaut Lake north of east into the Cussewago Valley, at the bend 3 or 

 4 miles west of Meadville, the other passing from near Conueautville to the 

 Cussewago Valley at Crossingville. The Cussewago Valley has drift knolls 

 along its eastern side throughout the interval between Crossingville and the 

 bend of the creek, while the western slope is nearly free from drift knolls. 



