12 THE AMERICAN MIDLAND NATURALIST 



River are in west central Ohio. Along the Lake Erie-Ohio River drainage 

 divide, swampy forests and boggy tracts were once common. 



Points of interest within the area include the reservoirs for the now aban- 

 doned Miami and Erie Canal which are known as Indian Lake, Lake St. 

 Mary's and the Loramie Reservoir. All of these are well populated with 

 turtles. The highest and lowest points in Ohio are both in the till plains, 

 the former being at the summit of Campbell Hill in Logan County, which 

 attains an elevation of 1550 feet, and the latter being at Cincinnati where the 

 low water level of the Ohio River is 428 feet above sea level. 



Centered in Logan and Champaign Counties are a number of large 

 moraines among which lie several bogs of small size. Drainage from this 

 area is rapid and gives rise to such streams as the Mad River, one of the very 

 few clear streams of large size in Ohio. Near Urbana, Champaign County, 

 is a small arbor vitae bog, apparently the only one of its kind in the state. 

 In it Clemmys guttata is common and at one time Ststrurus catenatus caten- 

 atus was numerous about its borders. 



In the extreme northwestern part of Ohio the till plains are characterized 

 by small lakes and tamarack-sphagnum bogs, such as are common in the adja- 

 cent parts of Indiana and Michigan. This is the only portion of the till plains 

 in which Emys blandingii is indigenous. 



In the counties bordering the Ohio River are many deep, rocky, well 

 wooded ravines. In, and near these, several species occur in numbers which 

 are also common in the unglaciated plateau, but which are either rare or 

 absent in other parts of the till plains. These include Sceloporus undulatus, 

 Eumeces laticeps, Heterodon contortrix, Opheodrys aestivus, Coluber con- 

 strictor constrictor and Agkistrodon mokasen mokasen. 



Almost the entire till plains area is extensively cultivated or has been at 

 some time. The original forest has disappeared and ditching and tiling have 

 lowered the water table considerably. Collecting, except in a few areas, was 

 poor, and field activities, on the whole, were less successful in the till plains 

 than in any of the other physiographic areas. Matrix sipedon sipedon and 

 Natrix septemvittata, however, are almost universally common along the 

 streams. 



Despite the comparative scarcity of reptiles the till plains is the richest 

 area in number of species recorded, but this is due in a large measure to the 

 proximity of more favorable habitats near the edges of the adjacent regions. 

 Three species of lizards, twenty-one snakes and ten turtles, or a total of thirty- 

 four forms were taken in the till plains. Of this number, however, no less 

 than thirteen barely enter its borders or are confined to more or less limited 

 areas. In addition to Emys, Sceloporus, Heterodon, Agkistrodon, etc. men- 

 tioned above, the following species show such a limited distribution in the till 

 plains: Carphophis amoena helenae, Storeria occipito-maculata, Virginia 

 valeriae valeriae, Pseudemys scripta troostii and Amyda mutica. 



Natrix erythrogaster erythrogaster is the only Ohio species collected exclu- 



