March, 1908.] Two Notable Landslides. 287 



TWO NOTABLE LANDSLIDES.* 



George D. Hubbard. 



The landslide is the sort of phenomenon to have caught the 

 attention of the geologist of a century ago, but with our present 

 substantial grounding in uniformitarianism, and in our attempt 

 to appreciate duly the ordinary, we are more than likely to under- 

 estimate the importance of the extraordinary. Hence, I want to 

 call attention to this rather remarkable, and, in some localities, 

 prevalent, process of denudation. 



In many of the newer valleys of southeastern Ohio, land slide 

 topography is almost omnipresent. Hundreds of acres of land 

 along the steeper A^alley walls have been ruined or badly dam- 

 aged for agriculture by slipping, and tumbling down the slopes, 

 or by being covered with material which has tumbled down. 

 The sliding usually so mixes the soil with the subsoil, or that part, 

 of the regolith yet unprepared for supporting plant growth, that 

 the soil can no longer be used. Further, the tumbled, bunchy 

 condition of a landslide prevents cultivation and harvesting, and 

 even hurts the area seriously for pasture. 



Within historic time, there have been thousands of land- 

 slides of various sizes in the hilly part of this state, and manv 

 occur every year even down to the present time. In the aggre- 

 gate they must be rather important physiographic phenomena. 

 During the past sixteen months a considerable number of minor,, 

 fresh heaps of tumbled debris have been examined, and two very 

 extensive piles have been studied. 



The first notable landslide studied in Ohio occurred in the 

 spring of 190(), near the training track of a Mr. Corwine, about 

 two miles up the Scioto from Waverly. The upper (Pre-Wis- 

 consin) out wash terraces are here verv extensively developed, 

 and well preserved. Going northward or northwestward across 

 the level upper terrace-top past the training track, one approaches- 

 a place where an area comprising many acres of the terrace has 

 gone down 1-25 feet and slipped forward toward the stream 

 carrying fine rich pasture and scattered, old oaks down with it. 

 The slip has the appearance of recency. The section through 

 the outwash here is, from the top downward, washed gravel and 

 sand with much fine, poorly-sorted, material, 25-30 feet; then 

 blue clays and fine sands ideally stratified and containing, occa- 

 sionally, strata of brown iron-stained sand, or layers bearing 

 black sand of garnets, magnetite and some more valuable metal- 

 lic oxides. This fine clay and sand attains an exposed thickness 



* By permission of the State Geologist of Ohio. Read at the meeting 

 of the Ohio State Academ}^ of Science, 1907. 



