347 



desceuds westward to Yonngstowu on tbo Maboiiins. Borings at Niles and 

 Rome readied level at 70 feet above Lake Erie, sbowing tbat tbe old Grand 

 valley grows deeper in tbe nortb (65: 149-51). 



Tbey are marked off by tbe meridians of New Martinsville and Colum- 

 bus and include a mass of detail tbat, in most cases, is very difficult to map 

 from tbe text. Tbe area soutb of a line between New Martinsville and tbe 

 moutb of Newark river bas been studied tborougbly by Tigbt and mapped 

 in detail (PI. V and 109) and well discussed. Tbe cbanges bere are quite 

 profound but tbey can be read witb little difficulty. 



Theb Muskingum bas offered mucb difficulty to its own solution, es- 

 pecially witbin tbe deeply drift-covered areas. Leverett (65: 158-65) gives 

 tbe most concise summary of tbe preglacial conditions of tbe basin, but 

 Tigbt (109, PI. I) gives a similar general outline, and witb local writers 

 discusses tbe region. 



Tbe Blue Rock col is sufficiently plain to separate tbat part of tbe 

 present stream into nortb tiowing and soutb flowing portions. Tbe nortb 

 flowing part migbt bave gone nortb along tbe present Muskingum or 

 nortbwest up tbe Licking, but Leverett favors tbe latter (65: 161). Tigbt 

 is especially responsible for tbe section drained by tbe Licking reversed and 

 tbe preglacial Newark (104: 152, PI. I ; 91 : 160) and of Vernon river. 



Mucb difficulty was experienced in determining tbe location of tbe pre- 

 glacial ebannel wbicb carried tbe drainage of tbe present Muskingum after 

 it reacbes tbe beadwaters of tbe present Rocky river. Todd (117), a local 

 writer wbo bas a paper on tbe preglacial drainage of tbe Rocky basin and 

 an area soutb, favors an outlet down tbe preglacial Rocky, but Leverett 

 (65: 165) believes tbat it flowed east into tbe old Cuyaboga (PL IV), 

 altbougb be admits tbat tbe evidence of a slope in tbe rock floor in tbat 

 direction is meager. He also favors tbe idea tbat tbe upper Tuscarawas 

 was continuous witb tbe pi-eglacial Cuyaboga. 



Tbe system of preglacial drainage (Pis. IV, V) collected into Ports- 

 moutb river — tbe lower Scioto reversed — is fully discussed by Tight, Lev- 

 erett and otbers and is establisbecl. Newark, Vernon and Portsmouth 

 rivers united somewhere southwest of Columbus, but it is not well known 

 just where. After the union of these rivers the direction of their united 

 valleys is not yet determined. Leverett (65: 103-4) says on the question: 

 ""Four possible courses were suggested f<ir tbe discbarge from the southern 

 cud of the Sciot(> basin: First, southward, down llic Scioto from Waverly 



