242 



more particiilarly about the east end of the Wea Plains ah)n,ii ravines 

 opening- into the Big Wea Creek. An exposure 3.r> miles south of La Fay- 

 ette shows a deep layer of false bedded tine sand overlaid by three feet of 

 very dense till, aliove wliicli is ten feet of sand and gravel. This inter- 

 stratittcation of materials ajipears even more strongly marked along die 

 Wild Cat Creeks. At the bridge across South Forlc near Monitor are two 

 lieds of clay differing in cdlor and (iverlaid liy twenty feet of saml and 

 gravel. Near ryrnKuit. im I lie ndrlli fori;, ten fi'ct of dark alluvial clay 

 apiiears above the waters of tlie creek, aliove this ten feet of coarse gravel, 

 and above this forty feet of gray bowlder clay. 



Alliid 'rojioura iihji.—'Vlu^ topcgrapliy of the county al)out the liorder of 

 the terrace deposits is interesting and suggestive. A moraine ridge con- 

 taining much gravel, some of it water laid, extends along the entire south 

 side of tlie Wea I'lains. A heavy moraine lies along the north side of the 

 valley from Battle (Jround south, bending away from the river jus" above 

 West LaFayette. Stream sections in the mass of this moraine show com- 

 pact till as deep as they extend. At the mouth of Indian Creek the upper 

 hundred feet of tlie l)lulT is a layer of tine sand resembling the dune sand 

 of Lake Michigan, and tlie sand ridges of northern Indiana. Tliis may be 

 the source of the sand built into the ridges and dunes a mile further up 

 the valley. The liluffs back of LaFayette are of till and are possibly a 

 section of the moraine west of the river extending east in the direction of 

 Monitor. 



E.riiliiiKilinii.— \\\ attemjit at exiilaiialioii wouhl revert immediately to 

 the glacial period. The great valley was obstrui-ted somewhere to the 

 west, probably in the region of the great bend, by an ice sheet moving east 

 or south. This may have been a result of one of tlie earlier ice invasions. 

 The obstructed valley fornnng a lake has licen Hlled liy the deltas of 

 streams flowing into it. The high angle of the layers indicate this. The 

 layers of till represent movements of the ice sheet over the delta jilain. 

 These may have lieen minor advances and recessions of the same ice 

 sheet. The material has lieen assorted out of the drift sheet overlying 

 the basins of the streams traversing tlie region. The lime cement in the 

 conglomerate is easily explained as ln-ing derived from the Niagara lime- 

 stone region l.ving immediately to tlie east. 



The prolilems in detail are of such complexity that any attempt at ex- 

 planation is made with extreme diffidence. There are good reasons for 

 believing that the valley was over-ridden by ice from the east and also 



